Beam failure recovery request transmission

ABSTRACT

Systems, apparatuses, and methods are described for wireless communications. A base station may transmit an indication of a type of a beam failure recovery request. A wireless device may detect a beam failure and transmit a beam failure recovery requested based on the type.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/543,816, titled “BFR Request Transmission,” which was filed on Aug.10, 2017, and which is hereby incorporated by reference in its entirety.

BACKGROUND

In wireless communications, beam failure recovery may be used fordetermining a candidate beam upon a beam failure. If a beam failure isdetected, difficulties may arise in determining a new beam in a timelyand efficient manner.

SUMMARY

The following summary presents a simplified summary of certain features.The summary is not an extensive overview and is not intended to identifykey or critical elements.

Systems, apparatuses, and methods are described for communicationsassociated with beam failure recovery. A base station may determine atype of a beam failure recovery for a wireless device. The base stationmay transmit, to the wireless device, one or more messages comprisingconfiguration parameters. The configuration parameters may comprise anindication of the type of a beam failure recovery for the wirelessdevice. The wireless device may detect a beam failure. Based on the typeof a beam failure, the wireless device may transmit a beam failurerecovery request with or without an indication of one or more candidatebeams.

These and other features and advantages are described in greater detailbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

Some features are shown by way of example, and not by limitation, in theaccompanying drawings. In the drawings, like numerals reference similarelements.

FIG. 1 shows example sets of orthogonal frequency division multiplexing(OFDM) subcarriers.

FIG. 2 shows example transmission time and reception time for twocarriers in a carrier group.

FIG. 3 shows example OFDM radio resources.

FIG. 4 shows hardware elements of a base station and a wireless device.

FIG. 5A, FIG. 5B, FIG. 5C and FIG. 5D show examples for uplink anddownlink signal transmission.

FIG. 6 shows an example protocol structure with multi-connectivity.

FIG. 7 shows an example protocol structure with carrier aggregation (CA)and dual connectivity (DC).

FIG. 8 shows example timing advance group (TAG) configurations.

FIG. 9 shows example message flow in a random access process in asecondary TAG.

FIG. 10A and FIG. 10B show examples for interfaces between a 5G corenetwork and base stations.

FIG. 11A, FIG. 11B, FIG. 11C, FIG. 11D, FIG. 11E, and FIG. 11F showexamples for architectures of tight interworking between a 5G RAN and along term evolution (LTE) radio access network (RAN).

FIG. 12A, FIG. 12B, and FIG. 12C show examples for radio protocolstructures of tight interworking bearers.

FIG. 13A and FIG. 13B show examples for gNodeB (gNB) deployment.

FIG. 14 shows functional split option examples of a centralized gNBdeployment.

FIG. 15 shows an example of a synchronization signal burst set.

FIG. 16 shows an example of a random access procedure.

FIG. 17 shows an example of transmitting channel state informationreference signals periodically for a beam.

FIG. 18 shows an example of a channel state information reference signalmapping.

FIG. 19 shows an example of a beam failure event involving a singletransmission and receiving point.

FIG. 20 shows an example of a beam failure event involving multipletransmission and receiving points.

FIG. 21 shows an example of beam failure request transmissions withdifferent request types.

FIG. 22 shows an example of radio resource control (RRC) configurationsfor multiple beams.

FIG. 23 shows an example of processes for a wireless device for beamfailure recovery requests.

FIG. 24 shows an example of processes for a base station for beamfailure recovery requests.

FIG. 25 shows an example of processes for a base station to determine abeam failure request type.

FIG. 26 shows example elements of a computing device that may be used toimplement any of the various devices described herein.

DETAILED DESCRIPTION

The accompanying drawings, which form a part hereof, show examples ofthe disclosure. It is to be understood that the examples shown in thedrawings and/or discussed herein are non-exclusive and that there areother examples of how the disclosure may be practiced.

Examples may enable operation of carrier aggregation and may be employedin the technical field of multicarrier communication systems. Examplesmay relate to beam failure recovery in a multicarrier communicationsystem.

The following acronyms are used throughout the present disclosure,provided below for convenience although other acronyms may be introducedin the detailed description:

3GPP 3rd Generation Partnership Project

5G 5th generation wireless systems

5GC 5G Core Network

ACK Acknowledgement

AMF Access and Mobility Management Function

ASIC application-specific integrated circuit

BFR beam failure recovery

BPSK binary phase shift keying

CA carrier aggregation

CC component carrier

CDMA code division multiple access

CP cyclic prefix

CPLD complex programmable logic devices

CSI channel state information

CSS common search space

CU central unit

DC dual connectivity

DCI downlink control information

DFTS-OFDM discrete fourier transform spreading OFDM

DL downlink

DU distributed unit

eLTE enhanced LTE

eMBB enhanced mobile broadband

eNB evolved Node B

EPC evolved packet core

E-UTRAN evolved-universal terrestrial radio access network

FDD frequency division multiplexing

FPGA field programmable gate arrays

Fs-C Fs-control plane

Fs-U Fs-user plane

gNB next generation node B

HARQ hybrid automatic repeat request

HDL hardware description languages

ID identifier

IE information element

LTE long term evolution

MAC media access control

MCG master cell group

MeNB master evolved node B

MIB master information block

MME mobility management entity

mMTC massive machine type communications

NACK Negative Acknowledgement

NAS non-access stratum

NG CP next generation control plane core

NGC next generation core

NG-C NG-control plane

NG-U NG-user plane

NR MAC new radio MAC

NR PDCP new radio PDCP

NR PHY new radio physical

NR RLC new radio RLC

NR RRC new radio RRC

NR new radio

NSSAI network slice selection assistance information

OFDM orthogonal frequency division multiplexing

PCC primary component carrier

PCell primary cell

PDCCH physical downlink control channel

PDCP packet data convergence protocol

PDU packet data unit

PHICH physical HARQ indicator channel

PHY physical

PLMN public land mobile network

PSCell primary secondary cell

pTAG primary timing advance group

PUCCH physical uplink control channel

PUSCH physical uplink shared channel

QAM quadrature amplitude modulation

QPSK quadrature phase shift keying

RA random access

RACH random access channel

RAN radio access network

RAP random access preamble

RAR random access response

RB resource blocks

RBG resource block groups

RLC radio link control

RRC radio resource control

RRM radio resource management

RV redundancy version

SCC secondary component carrier

SCell secondary cell

SCG secondary cell group

SC-OFDM single carrier-OFDM

SDU service data unit

SeNB secondary evolved node B

SFN system frame number

S-GW serving gateway

SIB system information block

SC-OFDM single carrier orthogonal frequency division multiplexing

SRB signaling radio bearer

sTAG(s) secondary timing advance group(s)

TA timing advance

TAG timing advance group

TAI tracking area identifier

TAT time alignment timer

TDD time division duplexing

TDMA time division multiple access

TTI transmission time interval

TB transport block

UE user equipment

UL uplink

UPGW user plane gateway

URLLC ultra-reliable low-latency communications

VHDL VHSIC hardware description language

Xn-C Xn-control plane

Xn-U Xn-user plane

Xx-C Xx-control plane

Xx-U Xx-user plane

Examples may be implemented using various physical layer modulation andtransmission mechanisms. Example transmission mechanisms may include,but are not limited to: CDMA, OFDM, TDMA, Wavelet technologies, and/orthe like. Hybrid transmission mechanisms such as TDMA/CDMA, andOFDM/CDMA may also be employed. Various modulation schemes may be usedfor signal transmission in the physical layer. Examples of modulationschemes include, but are not limited to: phase, amplitude, code, acombination of these, and/or the like. An example radio transmissionmethod may implement QAM using BPSK, QPSK, 16-QAM, 64-QAM, 256-QAM,and/or the like. Physical radio transmission may be enhanced bydynamically or semi-dynamically changing the modulation and codingscheme depending on transmission requirements and radio conditions.

FIG. 1 shows example sets of OFDM subcarriers. As shown in this example,arrow(s) in the diagram may depict a subcarrier in a multicarrier OFDMsystem. The OFDM system may use technology such as OFDM technology,DFTS-OFDM, SC-OFDM technology, or the like. For example, arrow 101 showsa subcarrier transmitting information symbols. FIG. 1 is shown as anexample, and a typical multicarrier OFDM system may include moresubcarriers in a carrier. For example, the number of subcarriers in acarrier may be in the range of 10 to 10,000 subcarriers. FIG. 1 showstwo guard bands 106 and 107 in a transmission band. As shown in FIG. 1,guard band 106 is between subcarriers 103 and subcarriers 104. Theexample set of subcarriers A 102 includes subcarriers 103 andsubcarriers 104. FIG. 1 also shows an example set of subcarriers B 105.As shown, there is no guard band between any two subcarriers in theexample set of subcarriers B 105. Carriers in a multicarrier OFDMcommunication system may be contiguous carriers, non-contiguouscarriers, or a combination of both contiguous and non-contiguouscarriers.

FIG. 2 shows an example timing arrangement with transmission time andreception time for two carriers. A multicarrier OFDM communicationsystem may include one or more carriers, for example, ranging from 1 to10 carriers. Carrier A 204 and carrier B 205 may have the same ordifferent timing structures. Although FIG. 2 shows two synchronizedcarriers, carrier A 204 and carrier B 205 may or may not be synchronizedwith each other. Different radio frame structures may be supported forFDD and TDD duplex mechanisms. FIG. 2 shows an example FDD frame timing.Downlink and uplink transmissions may be organized into radio frames201. In this example, radio frame duration is 10 milliseconds (msec).Other frame durations, for example, in the range of 1 to 100 msec mayalso be supported. In this example, each 10 msec radio frame 201 may bedivided into ten equally sized subframes 202. Other subframe durationssuch as including 0.5 msec, 1 msec, 2 msec, and 5 msec may also besupported. Subframe(s) may consist of two or more slots (e.g., slots 206and 207). For the example of FDD, 10 subframes may be available fordownlink transmission and 10 subframes may be available for uplinktransmissions in each 10 msec interval. Uplink and downlinktransmissions may be separated in the frequency domain. A slot may be 7or 14 OFDM symbols for the same subcarrier spacing of up to 60 kHz withnormal CP. A slot may be 14 OFDM symbols for the same subcarrier spacinghigher than 60 kHz with normal CP. A slot may include all downlink, alluplink, or a downlink part and an uplink part, and/or alike. Slotaggregation may be supported, e.g., data transmission may be scheduledto span one or multiple slots. For example, a mini-slot may start at anOFDM symbol in a subframe. A mini-slot may have a duration of one ormore OFDM symbols. Slot(s) may include a plurality of OFDM symbols 203.The number of OFDM symbols 203 in a slot 206 may depend on the cyclicprefix length and subcarrier spacing.

FIG. 3 shows an example of OFDM radio resources, including a resourcegrid structure in time 304 and frequency 305. The quantity of downlinksubcarriers or RBs may depend, at least in part, on the downlinktransmission bandwidth 306 configured in the cell. The smallest radioresource unit may be called a resource element (e.g., 301). Resourceelements may be grouped into resource blocks (e.g., 302). Resourceblocks may be grouped into larger radio resources called Resource BlockGroups (RBG) (e.g., 303). The transmitted signal in slot 206 may bedescribed by one or several resource grids of a plurality of subcarriersand a plurality of OFDM symbols. Resource blocks may be used to describethe mapping of certain physical channels to resource elements. Otherpre-defined groupings of physical resource elements may be implementedin the system depending on the radio technology. For example, 24subcarriers may be grouped as a radio block for a duration of 5 msec. Aresource block may correspond to one slot in the time domain and 180 kHzin the frequency domain (for 15 kHz subcarrier bandwidth and 12subcarriers).

Multiple numerologies may be supported. A numerology may be derived byscaling a basic subcarrier spacing by an integer N. Scalable numerologymay allow at least from 15 kHz to 480 kHz subcarrier spacing. Thenumerology with 15 kHz and scaled numerology with different subcarrierspacing with the same CP overhead may align at a symbol boundary every 1msec in a NR carrier.

FIG. 4 shows hardware elements of a base station 401 and a wirelessdevice 406. A communication network 400 may include at least one basestation 401 and at least one wireless device 406. The base station 401may include at least one communication interface 402, one or moreprocessors 403, and at least one set of program code instructions 405stored in non-transitory memory 404 and executable by the one or moreprocessors 403. The wireless device 406 may include at least onecommunication interface 407, one or more processors 408, and at leastone set of program code instructions 410 stored in non-transitory memory409 and executable by the one or more processors 408. A communicationinterface 402 in the base station 401 may be configured to engage incommunication with a communication interface 407 in the wireless device406, such as via a communication path that includes at least onewireless link 411. The wireless link 411 may be a bi-directional link.The communication interface 407 in the wireless device 406 may also beconfigured to engage in communication with the communication interface402 in the base station 401. The base station 401 and the wirelessdevice 406 may be configured to send and receive data over the wirelesslink 411 using multiple frequency carriers. Base stations, wirelessdevices, and other communication devices may include structure andoperations of transceiver(s). A transceiver is a device that includesboth a transmitter and receiver. Transceivers may be employed in devicessuch as wireless devices, base stations, relay nodes, and/or the like.Examples for radio technology implemented in the communicationinterfaces 402, 407 and the wireless link 411 are shown in FIG. 1, FIG.2, FIG. 3, FIG. 5, and associated text. The communication network 400may comprise any number and/or type of devices, such as, for example,computing devices, wireless devices, mobile devices, handsets, tablets,laptops, internet of things (IoT) devices, hotspots, cellular repeaters,computing devices, and/or, more generally, user equipment (e.g., UE).Although one or more of the above types of devices may be referencedherein (e.g., UE, wireless device, computing device, etc.), it should beunderstood that any device herein may comprise any one or more of theabove types of devices or similar devices. The communication network400, and any other network referenced herein, may comprise an LTEnetwork, a 5G network, or any other network for wireless communications.Apparatuses, systems, and/or methods described herein may generally bedescribed as implemented on one or more devices (e.g., wireless device,base station, eNB, gNB, computing device, etc.), in one or morenetworks, but it will be understood that one or more features and stepsmay be implemented on any device and/or in any network. As usedthroughout, the term “base station” may comprise one or more of: a basestation, a node, a Node B, a gNB, an eNB, an ng-eNB, a relay node (e.g.,an integrated access and backhaul (IAB) node), a donor node (e.g., adonor eNB, a donor gNB, etc.), an access point (e.g., a WiFi accesspoint), a computing device, a device capable of wirelesslycommunicating, or any other device capable of sending and/or receivingsignals. As used throughout, the term “wireless device” may comprise oneor more of: a UE, a handset, a mobile device, a computing device, anode, a device capable of wirelessly communicating, or any other devicecapable of sending and/or receiving signals. Any reference to one ormore of these terms/devices also considers use of any other term/devicementioned above.

The communications network 400 may comprise Radio Access Network (RAN)architecture. The RAN architecture may comprise one or more RAN nodesthat may be a next generation Node B (gNB) (e.g., 401) providing NewRadio (NR) user plane and control plane protocol terminations towards afirst wireless device (e.g. 406). A RAN node may be a next generationevolved Node B (ng-eNB), providing Evolved UMTS Terrestrial Radio Access(E-UTRA) user plane and control plane protocol terminations towards asecond wireless device. The first wireless device may communicate with agNB over a Uu interface. The second wireless device may communicate witha ng-eNB over a Uu interface. Base station 401 may comprise one or moreof a gNB, ng-eNB, and/or the like.

A gNB or an ng-eNB may host functions such as: radio resource managementand scheduling, IP header compression, encryption and integrityprotection of data, selection of Access and Mobility Management Function(AMF) at User Equipment (UE) attachment, routing of user plane andcontrol plane data, connection setup and release, scheduling andtransmission of paging messages (originated from the AMF), schedulingand transmission of system broadcast information (originated from theAMF or Operation and Maintenance (O&M)), measurement and measurementreporting configuration, transport level packet marking in the uplink,session management, support of network slicing, Quality of Service (QoS)flow management and mapping to data radio bearers, support of wirelessdevices in RRC_INACTIVE state, distribution function for Non-AccessStratum (NAS) messages, RAN sharing, and dual connectivity or tightinterworking between NR and E-UTRA.

One or more gNBs and/or one or more ng-eNBs may be interconnected witheach other by means of Xn interface. A gNB or an ng-eNB may be connectedby means of NG interfaces to 5G Core Network (5GC). 5GC may comprise oneor more AMF/User Plane Function (UPF) functions. A gNB or an ng-eNB maybe connected to a UPF by means of an NG-User plane (NG-U) interface. TheNG-U interface may provide delivery (e.g., non-guaranteed delivery) ofuser plane Protocol Data Units (PDUs) between a RAN node and the UPF. AgNB or an ng-eNB may be connected to an AMF by means of an NG-Controlplane (e.g., NG-C) interface. The NG-C interface may provide functionssuch as NG interface management, UE context management, UE mobilitymanagement, transport of NAS messages, paging, PDU session management,configuration transfer or warning message transmission.

A UPF may host functions such as anchor point for intra-/inter-RadioAccess Technology (RAT) mobility (if applicable), external PDU sessionpoint of interconnect to data network, packet routing and forwarding,packet inspection and user plane part of policy rule enforcement,traffic usage reporting, uplink classifier to support routing trafficflows to a data network, branching point to support multi-homed PDUsession, QoS handling for user plane, e.g. packet filtering, gating,Uplink (UL)/Downlink (DL) rate enforcement, uplink traffic verification(e.g. Service Data Flow (SDF) to QoS flow mapping), downlink packetbuffering and/or downlink data notification triggering.

An AMF may host functions such as NAS signaling termination, NASsignaling security, Access Stratum (AS) security control, inter CoreNetwork (CN) node signaling for mobility between 3^(rd) GenerationPartnership Project (3GPP) access networks, idle mode UE reachability(e.g., control and execution of paging retransmission), registrationarea management, support of intra-system and inter-system mobility,access authentication, access authorization including check of roamingrights, mobility management control (subscription and policies), supportof network slicing and/or Session Management Function (SMF) selection

An interface may be a hardware interface, a firmware interface, asoftware interface, and/or a combination thereof. The hardware interfacemay include connectors, wires, electronic devices such as drivers,amplifiers, and/or the like. A software interface may include codestored in a memory device to implement protocol(s), protocol layers,communication drivers, device drivers, combinations thereof, and/or thelike. A firmware interface may include a combination of embeddedhardware and code stored in and/or in communication with a memory deviceto implement connections, electronic device operations, protocol(s),protocol layers, communication drivers, device drivers, hardwareoperations, combinations thereof, and/or the like.

The term configured may relate to the capacity of a device whether thedevice is in an operational or a non-operational state. Configured mayalso refer to specific settings in a device that effect the operationalcharacteristics of the device whether the device is in an operational ora non-operational state. In other words, the hardware, software,firmware, registers, memory values, and/or the like may be “configured”within a device, whether the device is in an operational or anonoperational state, to provide the device with specificcharacteristics. Terms such as “a control message to cause in a device”may mean that a control message has parameters that may be used toconfigure specific characteristics in the device, whether the device isin an operational or a non-operational state.

A 5G network may include a multitude of base stations, providing a userplane NR PDCP/NR RLC/NR MAC/NR PHY and control plane (NR RRC) protocolterminations towards the wireless device. The base station(s) may beinterconnected with other base station(s) (e.g., employing an Xninterface). The base stations may also be connected employing, forexample, an NG interface to an NGC. FIG. 10A and FIG. 10B show examplesfor interfaces between a 5G core network (e.g., NGC) and base stations(e.g., gNB and eLTE eNB). For example, the base stations may beinterconnected to the NGC control plane (e.g., NG CP) employing the NG-Cinterface and to the NGC user plane (e.g., UPGW) employing the NG-Uinterface. The NG interface may support a many-to-many relation between5G core networks and base stations.

A base station may include many sectors, for example: 1, 2, 3, 4, or 6sectors. A base station may include many cells, for example, rangingfrom 1 to 50 cells or more. A cell may be categorized, for example, as aprimary cell or secondary cell. At RRC connectionestablishment/re-establishment/handover, one serving cell may providethe NAS (non-access stratum) mobility information (e.g., TAI), and atRRC connection re-establishment/handover, one serving cell may providethe security input. This cell may be referred to as the Primary Cell(PCell). In the downlink, the carrier corresponding to the PCell may bethe Downlink Primary Component Carrier (DL PCC); in the uplink, thecarrier corresponding to the PCell may be the Uplink Primary ComponentCarrier (UL PCC). Depending on wireless device capabilities, SecondaryCells (SCells) may be configured to form together with the PCell a setof serving cells. In the downlink, the carrier corresponding to an SCellmay be a Downlink Secondary Component Carrier (DL SCC); in the uplink,the carrier corresponding to an SCell may be an Uplink SecondaryComponent Carrier (UL SCC). An SCell may or may not have an uplinkcarrier.

A cell, comprising a downlink carrier and optionally an uplink carrier,may be assigned a physical cell ID and a cell index. A carrier (downlinkor uplink) may belong to only one cell. The cell ID or cell index mayalso identify the downlink carrier or uplink carrier of the cell(depending on the context in which it is used). The cell ID may beequally referred to a carrier ID, and cell index may be referred tocarrier index. In implementation, the physical cell ID or cell index maybe assigned to a cell. A cell ID may be determined using asynchronization signal transmitted on a downlink carrier. A cell indexmay be determined using RRC messages. For example, reference to a firstphysical cell ID for a first downlink carrier may indicate that thefirst physical cell ID is for a cell comprising the first downlinkcarrier. The same concept may apply to, for example, carrier activation.Reference to a first carrier that is activated may indicate that thecell comprising the first carrier is activated.

A device may be configured to operate as needed by freely combining anyof the examples. The disclosed mechanisms may be performed if certaincriteria are met, for example, in a wireless device, a base station, aradio environment, a network, a combination of the above, and/or thelike. Example criteria may be based, at least in part, on for example,traffic load, initial system set up, packet sizes, trafficcharacteristics, a combination of the above, and/or the like. One ormore criteria may be satisfied. It may be possible to implement examplesthat selectively implement disclosed protocols.

A base station may communicate with a variety of wireless devices.Wireless devices may support multiple technologies, and/or multiplereleases of the same technology. Wireless devices may have some specificcapability(ies) depending on its wireless device category and/orcapability(ies). A base station may comprise multiple sectors. Referenceto a base station communicating with a plurality of wireless devices mayindicate that a base station may communicate with a subset of the totalwireless devices in a coverage area. A plurality of wireless devices ofa given LTE or 5G release, with a given capability and in a given sectorof the base station, may be used. The plurality of wireless devices mayrefer to a selected plurality of wireless devices, and/or a subset oftotal wireless devices in a coverage area which perform according todisclosed methods, and/or the like. There may be a plurality of wirelessdevices in a coverage area that may not comply with the disclosedmethods, for example, because those wireless devices perform based onolder releases of LTE or 5G technology.

A base station may transmit (e.g., to a wireless device) one or moremessages (e.g. RRC messages) that may comprise a plurality ofconfiguration parameters for one or more cells. One or more cells maycomprise at least one primary cell and at least one secondary cell. AnRRC message may be broadcasted or unicasted to the wireless device.Configuration parameters may comprise common parameters and dedicatedparameters.

Services and/or functions of an RRC sublayer may comprise at least oneof: broadcast of system information related to AS and NAS; paginginitiated by 5GC and/or NG-RAN; establishment, maintenance, and/orrelease of an RRC connection between a wireless device and NG-RAN, whichmay comprise at least one of addition, modification and release ofcarrier aggregation; or addition, modification, and/or release of dualconnectivity in NR or between E-UTRA and NR. Services and/or functionsof an RRC sublayer may further comprise at least one of securityfunctions comprising key management; establishment, configuration,maintenance, and/or release of Signaling Radio Bearers (SRBs) and/orData Radio Bearers (DRBs); mobility functions which may comprise atleast one of a handover (e.g. intra NR mobility or inter-RAT mobility)and a context transfer; or a wireless device cell selection andreselection and control of cell selection and reselection. Servicesand/or functions of an RRC sublayer may further comprise at least one ofQoS management functions; a wireless device measurementconfiguration/reporting; detection of and/or recovery from radio linkfailure; or NAS message transfer to/from a core network entity (e.g.AMF, Mobility Management Entity (MME)) from/to the wireless device.

An RRC sublayer may support an RRC_Idle state, an RRC_Inactive stateand/or an RRC_Connected state for a wireless device. In an RRC_Idlestate, a wireless device may perform at least one of: Public Land MobileNetwork (PLMN) selection; receiving broadcasted system information; cellselection/re-selection; monitoring/receiving a paging for mobileterminated data initiated by 5GC; paging for mobile terminated data areamanaged by 5GC; or DRX for CN paging configured via NAS. In anRRC_Inactive state, a wireless device may perform at least one of:receiving broadcasted system information; cell selection/re-selection;monitoring/receiving a RAN/CN paging initiated by NG-RAN/5GC; RAN-basednotification area (RNA) managed by NG-RAN; or DRX for RAN/CN pagingconfigured by NG-RAN/NAS. In an RRC_Idle state of a wireless device, abase station (e.g. NG-RAN) may keep a 5GC-NG-RAN connection (bothC/U-planes) for the wireless device; and/or store a UE AS context forthe wireless device. In an RRC_Connected state of a wireless device, abase station (e.g. NG-RAN) may perform at least one of: establishment of5GC-NG-RAN connection (both C/U-planes) for the wireless device; storinga UE AS context for the wireless device; transmit/receive of unicastdata to/from the wireless device; or network-controlled mobility basedon measurement results received from the wireless device. In anRRC_Connected state of a wireless device, an NG-RAN may know a cell thatthe wireless device belongs to.

System information (SI) may be divided into minimum SI and other SI. Theminimum SI may be periodically broadcast. The minimum SI may comprisebasic information required for initial access and information foracquiring any other SI broadcast periodically or provisioned on-demand,i.e. scheduling information. The other SI may either be broadcast, or beprovisioned in a dedicated manner, either triggered by a network or uponrequest from a wireless device. A minimum SI may be transmitted via twodifferent downlink channels using different messages (e.g.MasterInformationBlock and SystemInformationBlockType1). The other SImay be transmitted via SystemInformationBlockType2. For a wirelessdevice in an RRC_Connected state, dedicated RRC signaling may beemployed for the request and delivery of the other SI. For the wirelessdevice in the RRC_Idle state and/or the RRC_Inactive state, the requestmay trigger a random-access procedure.

A wireless device may send its radio access capability information whichmay be static. A base station may request what capabilities for awireless device to report based on band information. If allowed by anetwork, a temporary capability restriction request may be sent by thewireless device to signal the limited availability of some capabilities(e.g. due to hardware sharing, interference or overheating) to the basestation. The base station may confirm or reject the request. Thetemporary capability restriction may be transparent to 5GC (e.g., staticcapabilities may be stored in 5GC).

If CA is configured, a wireless device may have an RRC connection with anetwork. At RRC connection establishment/re-establishment/handoverprocedure, one serving cell may provide NAS mobility information, and atRRC connection re-establishment/handover, one serving cell may provide asecurity input. This cell may be referred to as the PCell. Depending onthe capabilities of the wireless device, SCells may be configured toform together with the PCell a set of serving cells. The configured setof serving cells for the wireless device may comprise one PCell and oneor more SCells.

The reconfiguration, addition and removal of SCells may be performed byRRC. At intra-NR handover, RRC may also add, remove, or reconfigureSCells for usage with the target PCell. If adding a new SCell, dedicatedRRC signaling may be employed to send all required system information ofthe SCell. In connected mode, wireless devices may not need to acquirebroadcasted system information directly from the SCells.

An RRC connection reconfiguration procedure may be used to modify an RRCconnection, (e.g. to establish, modify and/or release RBs, to performhandover, to setup, modify, and/or release measurements, to add, modify,and/or release SCells and cell groups). As part of the RRC connectionreconfiguration procedure, NAS dedicated information may be transferredfrom the network to the wireless device. TheRRCConnectionReconfiguration message may be a command to modify an RRCconnection. It may convey information for measurement configuration,mobility control, radio resource configuration (e.g. RBs, MAC mainconfiguration and physical channel configuration) comprising anyassociated dedicated NAS information and security configuration. If thereceived RRC Connection Reconfiguration message includes thesCellToReleaseList, the wireless device may perform an SCell release. Ifthe received RRC Connection Reconfiguration message includes thesCellToAddModList, the wireless device may perform SCell additions ormodification.

An RRC connection establishment (or reestablishment, resume) proceduremay be used to establish (or reestablish, resume) an RRC connection. AnRRC connection establishment procedure may comprise SRB1 establishment.The RRC connection establishment procedure may be used to transfer theinitial NAS dedicated information message from a wireless device toE-UTRAN. The RRCConnectionReestablishment message may be used tore-establish SRB1.

A measurement report procedure may be to transfer measurement resultsfrom a wireless device to NG-RAN. The wireless device may initiate ameasurement report procedure, e.g., after successful securityactivation. A measurement report message may be employed to transmitmeasurement results.

FIG. 5A, FIG. 5B, FIG. 5C, and FIG. 5D show examples of architecture foruplink and downlink signal transmission. FIG. 5A shows an example for anuplink physical channel. The baseband signal representing the physicaluplink shared channel may be processed according to the followingprocesses, which may be performed by structures described below. Thesestructures and corresponding functions are shown as examples, however,it is anticipated that other structures and/or functions may beimplemented in various examples. The structures and correspondingfunctions may comprise, e.g., one or more scrambling devices 501A and501B configured to perform scrambling of coded bits in each of thecodewords to be transmitted on a physical channel; one or moremodulation mappers 502A and 502B configured to perform modulation ofscrambled bits to generate complex-valued symbols; a layer mapper 503configured to perform mapping of the complex-valued modulation symbolsonto one or several transmission layers; one or more transform precoders504A and 504B to generate complex-valued symbols; a precoding device 505configured to perform precoding of the complex-valued symbols; one ormore resource element mappers 506A and 506B configured to performmapping of precoded complex-valued symbols to resource elements; one ormore signal generators 507A and 507B configured to perform thegeneration of a complex-valued time-domain DFTS-OFDM/SC-FDMA signal foreach antenna port; and/or the like.

FIG. 5B shows an example for performing modulation and up-conversion tothe carrier frequency of the complex-valued DFTS-OFDM/SC-FDMA basebandsignal, e.g., for each antenna port and/or for the complex-valuedphysical random access channel (PRACH) baseband signal. For example, thebaseband signal, represented as s₁(t), may be split, by a signalsplitter 510, into real and imaginary components, Re{s₁(t)} andIm{s₁(t)}, respectively. The real component may be modulated by amodulator 511A, and the imaginary component may be modulated by amodulator 511B. The output signal of the modulator 511A and the outputsignal of the modulator 511B may be mixed by a mixer 512. The outputsignal of the mixer 512 may be input to a filtering device 513, andfiltering may be employed by the filtering device 513 prior totransmission.

FIG. 5C shows an example structure for downlink transmissions. Thebaseband signal representing a downlink physical channel may beprocessed by the following processes, which may be performed bystructures described below. These structures and corresponding functionsare shown as examples, however, it is anticipated that other structuresand/or functions may be implemented in various examples. The structuresand corresponding functions may comprise, e.g., one or more scramblingdevices 531A and 531B configured to perform scrambling of coded bits ineach of the codewords to be transmitted on a physical channel; one ormore modulation mappers 532A and 532B configured to perform modulationof scrambled bits to generate complex-valued modulation symbols; a layermapper 533 configured to perform mapping of the complex-valuedmodulation symbols onto one or several transmission layers; a precodingdevice 534 configured to perform precoding of the complex-valuedmodulation symbols on each layer for transmission on the antenna ports;one or more resource element mappers 535A and 535B configured to performmapping of complex-valued modulation symbols for each antenna port toresource elements; one or more OFDM signal generators 536A and 536Bconfigured to perform the generation of complex-valued time-domain OFDMsignal for each antenna port; and/or the like.

FIG. 5D shows an example structure for modulation and up-conversion tothe carrier frequency of the complex-valued OFDM baseband signal foreach antenna port. For example, the baseband signal, represented as s₁^((p))(t), may be split, by a signal splitter 520, into real andimaginary components, Re{s₁ ^((p))(t)} and Im{s₁ ^((p))(t)},respectively. The real component may be modulated by a modulator 521A,and the imaginary component may be modulated by a modulator 521B. Theoutput signal of the modulator 521A and the output signal of themodulator 521B may be mixed by a mixer 522. The output signal of themixer 522 may be input to a filtering device 523, and filtering may beemployed by the filtering device 523 prior to transmission.

FIG. 6 and FIG. 7 show examples for protocol structures with CA andmulti-connectivity. NR may support multi-connectivity operation, wherebya multiple receiver/transmitter (RX/TX) wireless device in RRC_CONNECTEDmay be configured to utilize radio resources provided by multipleschedulers located in multiple gNBs connected via a non-ideal or idealbackhaul over the Xn interface. gNBs involved in multi-connectivity fora certain wireless device may assume two different roles: a gNB mayeither act as a master gNB (e.g., 600) or as a secondary gNB (e.g., 610or 620). In multi-connectivity, a wireless device may be connected toone master gNB (e.g., 600) and one or more secondary gNBs (e.g., 610and/or 620). Any one or more of the Master gNB 600 and/or the secondarygNBs 610 and 620 may be a Next Generation (NG) NodeB. The master gNB 600may comprise protocol layers NR MAC 601, NR RLC 602 and 603, and NR PDCP604 and 605. The secondary gNB may comprise protocol layers NR MAC 611,NR RLC 612 and 613, and NR PDCP 614. The secondary gNB may compriseprotocol layers NR MAC 621, NR RLC 622 and 623, and NR PDCP 624. Themaster gNB 600 may communicate via an interface 606 and/or via aninterface 607, the secondary gNB 610 may communicate via an interface615, and the secondary gNB 620 may communicate via an interface 625. Themaster gNB 600 may also communicate with the secondary gNB 610 and thesecondary gNB 621 via interfaces 608 and 609, respectively, which mayinclude Xn interfaces. For example, the master gNB 600 may communicatevia the interface 608, at layer NR PDCP 605, and with the secondary gNB610 at layer NR RLC 612. The master gNB 600 may communicate via theinterface 609, at layer NR PDCP 605, and with the secondary gNB 620 atlayer NR RLC 622.

FIG. 7 shows an example structure for the UE side MAC entities, e.g., ifa Master Cell Group (MCG) and a Secondary Cell Group (SCG) areconfigured. Media Broadcast Multicast Service (MBMS) reception may beincluded but is not shown in this figure for simplicity.

In multi-connectivity, the radio protocol architecture that a particularbearer uses may depend on how the bearer is set up. As an example, threealternatives may exist, an MCG bearer, an SCG bearer, and a splitbearer, such as shown in FIG. 6. NR RRC may be located in a master gNBand SRBs may be configured as a MCG bearer type and may use the radioresources of the master gNB. Multi-connectivity may have at least onebearer configured to use radio resources provided by the secondary gNB.Multi-connectivity may or may not be configured or implemented.

For multi-connectivity, the wireless device may be configured withmultiple NR MAC entities: e.g., one NR MAC entity for a master gNB, andother NR MAC entities for secondary gNBs. In multi-connectivity, theconfigured set of serving cells for a wireless device may comprise twosubsets: e.g., the Master Cell Group (MCG) including the serving cellsof the master gNB, and the Secondary Cell Groups (SCGs) including theserving cells of the secondary gNBs.

At least one cell in a SCG may have a configured UL component carrier(CC) and one of the UL CCs, e.g., named PSCell (or PCell of SCG, orsometimes called PCell), may be configured with PUCCH resources. If theSCG is configured, there may be at least one SCG bearer or one splitbearer. If a physical layer problem or a random access problem on aPSCell occurs or is detected, if the maximum number of NR RLCretransmissions has been reached associated with the SCG, or if anaccess problem on a PSCell during a SCG addition or a SCG change occursor is detected, then an RRC connection re-establishment procedure maynot be triggered, UL transmissions towards cells of the SCG may bestopped, a master gNB may be informed by the wireless device of a SCGfailure type, and for a split bearer the DL data transfer over themaster gNB may be maintained. The NR RLC Acknowledge Mode (AM) bearermay be configured for the split bearer. Like the PCell, a PSCell may notbe de-activated. The PSCell may be changed with an SCG change (e.g.,with a security key change and a RACH procedure). A direct bearer typemay change between a split bearer and an SCG bearer, or a simultaneousconfiguration of an SCG and a split bearer may or may not be supported.

A master gNB and secondary gNBs may interact for multi-connectivity. Themaster gNB may maintain the RRM measurement configuration of thewireless device, and the master gNB may, (e.g., based on receivedmeasurement reports, and/or based on traffic conditions and/or bearertypes), decide to ask a secondary gNB to provide additional resources(e.g., serving cells) for a wireless device. If a request from themaster gNB is received, a secondary gNB may create a container that mayresult in the configuration of additional serving cells for the wirelessdevice (or the secondary gNB decide that it has no resource available todo so). For wireless device capability coordination, the master gNB mayprovide some or all of the Active Set (AS) configuration and thewireless device capabilities to the secondary gNB. The master gNB andthe secondary gNB may exchange information about a wireless deviceconfiguration, such as by employing NR RRC containers (e.g., inter-nodemessages) carried in Xn messages. The secondary gNB may initiate areconfiguration of its existing serving cells (e.g., PUCCH towards thesecondary gNB). The secondary gNB may decide which cell is the PSCellwithin the SCG. The master gNB may or may not change the content of theNR RRC configuration provided by the secondary gNB. In an SCG additionand an SCG SCell addition, the master gNB may provide the latestmeasurement results for the SCG cell(s). Both a master gNB and asecondary gNBs may know the system frame number (SFN) and subframeoffset of each other by operations, administration, and maintenance(OAM) (e.g., for the purpose of discontinuous reception (DRX) alignmentand identification of a measurement gap). If adding a new SCG SCell,dedicated NR RRC signaling may be used for sending required systeminformation of the cell for CA, except, e.g., for the SFN acquired froman MIB of the PSCell of an SCG.

FIG. 7 shows an example of dual-connectivity (DC) for two MAC entitiesat a wireless device side. A first MAC entity may comprise a lower layerof an MCG 700, an upper layer of an MCG 718, and one or moreintermediate layers of an MCG 719. The lower layer of the MCG 700 maycomprise, e.g., a paging channel (PCH) 701, a broadcast channel (BCH)702, a downlink shared channel (DL-SCH) 703, an uplink shared channel(UL-SCH) 704, and a random access channel (RACH) 705. The one or moreintermediate layers of the MCG 719 may comprise, e.g., one or morehybrid automatic repeat request (HARQ) processes 706, one or more randomaccess control processes 707, multiplexing and/or de-multiplexingprocesses 709, logical channel prioritization on the uplink processes710, and a control processes 708 providing control for the aboveprocesses in the one or more intermediate layers of the MCG 719. Theupper layer of the MCG 718 may comprise, e.g., a paging control channel(PCCH) 711, a broadcast control channel (BCCH) 712, a common controlchannel (CCCH) 713, a dedicated control channel (DCCH) 714, a dedicatedtraffic channel (DTCH) 715, and a MAC control 716.

A second MAC entity may comprise a lower layer of an SCG 720, an upperlayer of an SCG 738, and one or more intermediate layers of an SCG 739.The lower layer of the SCG 720 may comprise, e.g., a BCH 722, a DL-SCH723, an UL-SCH 724, and a RACH 725. The one or more intermediate layersof the SCG 739 may comprise, e.g., one or more HARQ processes 726, oneor more random access control processes 727, multiplexing and/orde-multiplexing processes 729, logical channel prioritization on theuplink processes 730, and a control processes 728 providing control forthe above processes in the one or more intermediate layers of the SCG739. The upper layer of the SCG 738 may comprise, e.g., a BCCH 732, aDCCH 714, a DTCH 735, and a MAC control 736.

Serving cells may be grouped in a TA group (TAG). Serving cells in oneTAG may use the same timing reference. For a given TAG, a wirelessdevice may use at least one downlink carrier as a timing reference. Fora given TAG, a wireless device may synchronize uplink subframe and frametransmission timing of uplink carriers belonging to the same TAG.Serving cells having an uplink to which the same TA applies maycorrespond to serving cells hosted by the same receiver. A wirelessdevice supporting multiple TAs may support two or more TA groups. One TAgroup may include the PCell and may be called a primary TAG (pTAG). In amultiple TAG configuration, at least one TA group may not include thePCell and may be called a secondary TAG (sTAG). Carriers within the sameTA group may use the same TA value and/or the same timing reference. IfDC is configured, cells belonging to a cell group (e.g., MCG or SCG) maybe grouped into multiple TAGs including a pTAG and one or more sTAGs.

FIG. 8 shows example TAG configurations. In Example 1, a pTAG comprisesa PCell, and an sTAG comprises an SCell1. In Example 2, a pTAG comprisesa PCell and an SCell1, and an sTAG comprises an SCell2 and an SCell3. InExample 3, a pTAG comprises a PCell and an SCell1, and an sTAG1comprises an SCell2 and an SCell3, and an sTAG2 comprises a SCell4. Upto four TAGs may be supported in a cell group (MCG or SCG), and otherexample TAG configurations may also be provided. In various examples,structures and operations are described for use with a pTAG and an sTAG.Some of the examples may be used for configurations with multiple sTAGs.

An eNB may initiate an RA procedure, via a PDCCH order, for an activatedSCell. The PDCCH order may be sent on a scheduling cell of this SCell.If cross carrier scheduling is configured for a cell, the schedulingcell may be different than the cell that is employed for preambletransmission, and the PDCCH order may include an SCell index. At least anon-contention based RA procedure may be supported for SCell(s) assignedto sTAG(s).

FIG. 9 shows an example of random access processes, and a correspondingmessage flow, in a secondary TAG. A base station, such as an eNB, maytransmit an activation command 900 to a wireless device, such as a UE.The activation command 900 may be transmitted to activate an SCell. Thebase station may also transmit a PDDCH order 901 to the wireless device,which may be transmitted, e.g., after the activation command 900. Thewireless device may begin to perform a RACH process for the SCell, whichmay be initiated, e.g., after receiving the PDDCH order 901. A wirelessdevice may transmit to the base station (e.g., as part of a RACHprocess) a preamble 902 (e.g., Msg1), such as a random access preamble(RAP). The preamble 902 may be transmitted in response to the PDCCHorder 901. The wireless device may transmit the preamble 902 via anSCell belonging to an sTAG. Preamble transmission for SCells may becontrolled by a network using PDCCH format 1A. The base station may senda random access response (RAR) 903 (e.g., Msg2 message) to the wirelessdevice. The RAR 903 may be in response to the preamble 902 transmissionvia the SCell. The RAR 903 may be addressed to a random access radionetwork temporary identifier (RA-RNTI) in a PCell common search space(CSS). If the wireless device receives the RAR 903, the RACH process mayconclude. The RACH process may conclude, e.g., after or in response tothe wireless device receiving the RAR 903 from the base station. Afterthe RACH process, the wireless device may transmit an uplinktransmission 904. The uplink transmission 904 may comprise uplinkpackets transmitted via the same SCell used for the preamble 902transmission.

Initial timing alignment for communications between the wireless deviceand the base station may be performed through a random access procedure,such as described above regarding FIG. 9. The random access proceduremay involve a wireless device, such as a UE, transmitting a randomaccess preamble and a base station, such as an eNB, responding with aninitial TA command NTA (amount of timing advance) within a random accessresponse window. The start of the random access preamble may be alignedwith the start of a corresponding uplink subframe at the wireless deviceassuming NTA=0. The eNB may estimate the uplink timing from the randomaccess preamble transmitted by the wireless device. The TA command maybe derived by the eNB based on the estimation of the difference betweenthe desired UL timing and the actual UL timing. The wireless device maydetermine the initial uplink transmission timing relative to thecorresponding downlink of the sTAG on which the preamble is transmitted.

The mapping of a serving cell to a TAG may be configured by a servingeNB with RRC signaling. The mechanism for TAG configuration andreconfiguration may be based on RRC signaling. If an eNB performs anSCell addition configuration, the related TAG configuration may beconfigured for the SCell. An eNB may modify the TAG configuration of anSCell by removing (e.g., releasing) the SCell and adding (e.g.,configuring) a new SCell (with the same physical cell ID and frequency)with an updated TAG ID. The new SCell with the updated TAG ID mayinitially be inactive subsequent to being assigned the updated TAG ID.The eNB may activate the updated new SCell and start scheduling packetson the activated SCell. In some examples, it may not be possible tochange the TAG associated with an SCell, but rather, the SCell may needto be removed and a new SCell may need to be added with another TAG. Forexample, if there is a need to move an SCell from an sTAG to a pTAG, atleast one RRC message, such as at least one RRC reconfiguration message,may be sent to the wireless device. The at least one RRC message may besent to the wireless device to reconfigure TAG configurations, e.g., byreleasing the SCell and configuring the SCell as a part of the pTAG. If,e.g., an SCell is added or configured without a TAG index, the SCell maybe explicitly assigned to the pTAG. The PCell may not change its TAgroup and may be a member of the pTAG.

In LTE Release-10 and Release-11 CA, a PUCCH transmission is onlytransmitted on a PCell (e.g., a PSCell) to an eNB. In LTE-Release 12 andearlier, a wireless device may transmit PUCCH information on one cell(e.g., a PCell or a PSCell) to a given eNB. As the number of CA capablewireless devices increase, and as the number of aggregated carriersincrease, the number of PUCCHs and the PUCCH payload size may increase.Accommodating the PUCCH transmissions on the PCell may lead to a highPUCCH load on the PCell. A PUCCH on an SCell may be used to offload thePUCCH resource from the PCell. More than one PUCCH may be configured.For example, a PUCCH on a PCell may be configured and another PUCCH onan SCell may be configured. One, two, or more cells may be configuredwith PUCCH resources for transmitting CSI, acknowledgment (ACK), and/ornon-acknowledgment (NACK) to a base station. Cells may be grouped intomultiple PUCCH groups, and one or more cell within a group may beconfigured with a PUCCH. In some examples, one SCell may belong to onePUCCH group. SCells with a configured PUCCH transmitted to a basestation may be called a PUCCH SCell, and a cell group with a commonPUCCH resource transmitted to the same base station may be called aPUCCH group.

A MAC entity may have a configurable timer, e.g., timeAlignmentTimer,per TAG. The timeAlignmentTimer may be used to control how long the MACentity considers the serving cells belonging to the associated TAG to beuplink time aligned. If a Timing Advance Command MAC control element isreceived, the MAC entity may apply the Timing Advance Command for theindicated TAG; and/or the MAC entity may start or restart thetimeAlignmentTimer associated with a TAG that may be indicated by theTiming Advance Command MAC control element. If a Timing Advance Commandis received in a Random Access Response message for a serving cellbelonging to a TAG, the MAC entity may apply the Timing Advance Commandfor this TAG and/or start or restart the timeAlignmentTimer associatedwith this TAG. Additionally or alternatively, if the Random AccessPreamble is not selected by the MAC entity, the MAC entity may apply theTiming Advance Command for this TAG and/or start or restart thetimeAlignmentTimer associated with this TAG. If the timeAlignmentTimerassociated with this TAG is not running, the Timing Advance Command forthis TAG may be applied, and the timeAlignmentTimer associated with thisTAG may be started. If the contention resolution is not successful, atimeAlignmentTimer associated with this TAG may be stopped. If thecontention resolution is successful, the MAC entity may ignore thereceived Timing Advance Command. The MAC entity may determine whetherthe contention resolution is successful or whether the contentionresolution is not successful.

FIG. 10A and FIG. 10B show examples for interfaces between a 5G corenetwork (e.g., NGC) and base stations (e.g., gNB and eLTE eNB). A basestation, such as a gNB 1020, may be interconnected to an NGC 1010control plane employing an NG-C interface. The base station, e.g., thegNB 1020, may also be interconnected to an NGC 1010 user plane (e.g.,UPGW) employing an NG-U interface. As another example, a base station,such as an eLTE eNB 1040, may be interconnected to an NGC 1030 controlplane employing an NG-C interface. The base station, e.g., the eLTE eNB1040, may also be interconnected to an NGC 1030 user plane (e.g., UPGW)employing an NG-U interface. An NG interface may support a many-to-manyrelation between 5G core networks and base stations.

FIG. 11A, FIG. 11B, FIG. 11C, FIG. 11D, FIG. 11E, and FIG. 11F areexamples for architectures of tight interworking between a 5G RAN and anLTE RAN. The tight interworking may enable a multiplereceiver/transmitter (RX/TX) wireless device in an RRC_CONNECTED stateto be configured to utilize radio resources provided by two schedulerslocated in two base stations (e.g., an eLTE eNB and a gNB). The two basestations may be connected via a non-ideal or ideal backhaul over the Xxinterface between an LTE eNB and a gNB, or over the Xn interface betweenan eLTE eNB and a gNB. Base stations involved in tight interworking fora certain wireless device may assume different roles. For example, abase station may act as a master base station or a base station may actas a secondary base station. In tight interworking, a wireless devicemay be connected to both a master base station and a secondary basestation. Mechanisms implemented in tight interworking may be extended tocover more than two base stations.

A master base station may be an LTE eNB 1102A or an LTE eNB 1102B, whichmay be connected to EPC nodes 1101A or 1101B, respectively. Thisconnection to EPC nodes may be, e.g., to an MME via the S1-C interfaceand/or to an S-GW via the S1-U interface. A secondary base station maybe a gNB 1103A or a gNB 1103B, either or both of which may be anon-standalone node having a control plane connection via an Xx-Cinterface to an LTE eNB (e.g., the LTE eNB 1102A or the LTE eNB 1102B).In the tight interworking architecture of FIG. 11A, a user plane for agNB (e.g., the gNB 1103A) may be connected to an S-GW (e.g., the EPC1101A) through an LTE eNB (e.g., the LTE eNB 1102A), via an Xx-Uinterface between the LTE eNB and the gNB, and via an S1-U interfacebetween the LTE eNB and the S-GW. In the architecture of FIG. 11B, auser plane for a gNB (e.g., the gNB 1103B) may be connected directly toan S-GW (e.g., the EPC 1101B) via an S1-U interface between the gNB andthe S-GW.

A master base station may be a gNB 1103C or a gNB 1103D, which may beconnected to NGC nodes 1101C or 1101D, respectively. This connection toNGC nodes may be, e.g., to a control plane core node via the NG-Cinterface and/or to a user plane core node via the NG-U interface. Asecondary base station may be an eLTE eNB 1102C or an eLTE eNB 1102D,either or both of which may be a non-standalone node having a controlplane connection via an Xn-C interface to a gNB (e.g., the gNB 1103C orthe gNB 1103D). In the tight interworking architecture of FIG. 11C, auser plane for an eLTE eNB (e.g., the eLTE eNB 1102C) may be connectedto a user plane core node (e.g., the NGC 1101C) through a gNB (e.g., thegNB 1103C), via an Xn-U interface between the eLTE eNB and the gNB, andvia an NG-U interface between the gNB and the user plane core node. Inthe architecture of FIG. 11D, a user plane for an eLTE eNB (e.g., theeLTE eNB 1102D) may be connected directly to a user plane core node(e.g., the NGC 1101D) via an NG-U interface between the eLTE eNB and theuser plane core node.

A master base station may be an eLTE eNB 1102E or an eLTE eNB 1102F,which may be connected to NGC nodes 1101E or 1101F, respectively. Thisconnection to NGC nodes may be, e.g., to a control plane core node viathe NG-C interface and/or to a user plane core node via the NG-Uinterface. A secondary base station may be a gNB 1103E or a gNB 1103F,either or both of which may be a non-standalone node having a controlplane connection via an Xn-C interface to an eLTE eNB (e.g., the eLTEeNB 1102E or the eLTE eNB 1102F). In the tight interworking architectureof FIG. 11E, a user plane for a gNB (e.g., the gNB 1103E) may beconnected to a user plane core node (e.g., the NGC 1101E) through aneLTE eNB (e.g., the eLTE eNB 1102E), via an Xn-U interface between theeLTE eNB and the gNB, and via an NG-U interface between the eLTE eNB andthe user plane core node. In the architecture of FIG. 11F, a user planefor a gNB (e.g., the gNB 1103F) may be connected directly to a userplane core node (e.g., the NGC 1101F) via an NG-U interface between thegNB and the user plane core node.

FIG. 12A, FIG. 12B, and FIG. 12C are examples for radio protocolstructures of tight interworking bearers.

An LTE eNB 1201A may be an S1 master base station, and a gNB 1210A maybe an S1 secondary base station. An example for a radio protocolarchitecture for a split bearer and an SCG bearer is shown. The LTE eNB1201A may be connected to an EPC with a non-standalone gNB 1210A, via anXx interface between the PDCP 1206A and an NR RLC 1212A. The LTE eNB1201A may include protocol layers MAC 1202A, RLC 1203A and RLC 1204A,and PDCP 1205A and PDCP 1206A. An MCG bearer type may interface with thePDCP 1205A, and a split bearer type may interface with the PDCP 1206A.The gNB 1210A may include protocol layers NR MAC 1211A, NR RLC 1212A andNR RLC 1213A, and NR PDCP 1214A. An SCG bearer type may interface withthe NR PDCP 1214A.

A gNB 1201B may be an NG master base station, and an eLTE eNB 1210B maybe an NG secondary base station. An example for a radio protocolarchitecture for a split bearer and an SCG bearer is shown. The gNB1201B may be connected to an NGC with a non-standalone eLTE eNB 1210B,via an Xn interface between the NR PDCP 1206B and an RLC 1212B. The gNB1201B may include protocol layers NR MAC 1202B, NR RLC 1203B and NR RLC1204B, and NR PDCP 1205B and NR PDCP 1206B. An MCG bearer type mayinterface with the NR PDCP 1205B, and a split bearer type may interfacewith the NR PDCP 1206B. The eLTE eNB 1210B may include protocol layersMAC 1211B, RLC 1212B and RLC 1213B, and PDCP 1214B. An SCG bearer typemay interface with the PDCP 1214B.

An eLTE eNB 1201C may be an NG master base station, and a gNB 1210C maybe an NG secondary base station. An example for a radio protocolarchitecture for a split bearer and an SCG bearer is shown. The eLTE eNB1201C may be connected to an NGC with a non-standalone gNB 1210C, via anXn interface between the PDCP 1206C and an NR RLC 1212C. The eLTE eNB1201C may include protocol layers MAC 1202C, RLC 1203C and RLC 1204C,and PDCP 1205C and PDCP 1206C. An MCG bearer type may interface with thePDCP 1205C, and a split bearer type may interface with the PDCP 1206C.The gNB 1210C may include protocol layers NR MAC 1211C, NR RLC 1212C andNR RLC 1213C, and NR PDCP 1214C. An SCG bearer type may interface withthe NR PDCP 1214C.

In a 5G network, the radio protocol architecture that a particularbearer uses may depend on how the bearer is setup. At least threealternatives may exist, e.g., an MCG bearer, an SCG bearer, and a splitbearer, such as shown in FIG. 12A, FIG. 12B, and FIG. 12C. The NR RRCmay be located in a master base station, and the SRBs may be configuredas an MCG bearer type and may use the radio resources of the master basestation. Tight interworking may have at least one bearer configured touse radio resources provided by the secondary base station. Tightinterworking may or may not be configured or implemented.

The wireless device may be configured with two MAC entities: e.g., oneMAC entity for a master base station, and one MAC entity for a secondarybase station. In tight interworking, the configured set of serving cellsfor a wireless device may comprise of two subsets: e.g., the Master CellGroup (MCG) including the serving cells of the master base station, andthe Secondary Cell Group (SCG) including the serving cells of thesecondary base station.

At least one cell in a SCG may have a configured UL CC and one of them,e.g., a PSCell (or the PCell of the SCG, which may also be called aPCell), is configured with PUCCH resources. If the SCG is configured,there may be at least one SCG bearer or one split bearer. If one or moreof a physical layer problem or a random access problem is detected on aPSCell, if the maximum number of (NR) RLC retransmissions associatedwith the SCG has been reached, and/or if an access problem on a PSCellduring an SCG addition or during an SCG change is detected, then: an RRCconnection re-establishment procedure may not be triggered, ULtransmissions towards cells of the SCG may be stopped, a master basestation may be informed by the wireless device of a SCG failure type,and/or for a split bearer the DL data transfer over the master basestation may be maintained. The RLC AM bearer may be configured for thesplit bearer. Like the PCell, a PSCell may not be de-activated. A PSCellmay be changed with an SCG change, e.g., with security key change and aRACH procedure. A direct bearer type change, between a split bearer andan SCG bearer, may not be supported. Simultaneous configuration of anSCG and a split bearer may not be supported.

A master base station and a secondary base station may interact. Themaster base station may maintain the RRM measurement configuration ofthe wireless device. The master base station may determine to ask asecondary base station to provide additional resources (e.g., servingcells) for a wireless device. This determination may be based on, e.g.,received measurement reports, traffic conditions, and/or bearer types.If a request from the master base station is received, a secondary basestation may create a container that may result in the configuration ofadditional serving cells for the wireless device, or the secondary basestation may determine that it has no resource available to do so. Themaster base station may provide at least part of the AS configurationand the wireless device capabilities to the secondary base station,e.g., for wireless device capability coordination. The master basestation and the secondary base station may exchange information about awireless device configuration such as by using RRC containers (e.g.,inter-node messages) carried in Xn or Xx messages. The secondary basestation may initiate a reconfiguration of its existing serving cells(e.g., PUCCH towards the secondary base station). The secondary basestation may determine which cell is the PSCell within the SCG. Themaster base station may not change the content of the RRC configurationprovided by the secondary base station. If an SCG is added and/or an SCGSCell is added, the master base station may provide the latestmeasurement results for the SCG cell(s). Either or both of a master basestation and a secondary base station may know the SFN and subframeoffset of each other by OAM, (e.g., for the purpose of DRX alignment andidentification of a measurement gap). If a new SCG SCell is added,dedicated RRC signaling may be used for sending required systeminformation of the cell, such as for CA, except, e.g., for the SFNacquired from an MIB of the PSCell of an SCG.

FIG. 13A and FIG. 13B show examples for gNB deployment. A core 1301 anda core 1310 may interface with other nodes via RAN-CN interfaces. In anon-centralized deployment example, the full protocol stack (e.g., NRRRC, NR PDCP, NR RLC, NR MAC, and NR PHY) may be supported at one node,such as a gNB 1302, a gNB 1303, and/or an eLTE eNB or LTE eNB 1304.These nodes (e.g., the gNB 1302, the gNB 1303, and the eLTE eNB or LTEeNB 1304) may interface with one of more of each other via a respectiveinter-BS interface. In a centralized deployment example, upper layers ofa gNB may be located in a Central Unit (CU) 1311, and lower layers ofthe gNB may be located in Distributed Units (DU) 1312, 1313, and 1314.The CU-DU interface (e.g., Fs interface) connecting CU 1311 and DUs1312, 1312, and 1314 may be ideal or non-ideal. The Fs-C may provide acontrol plane connection over the Fs interface, and the Fs-U may providea user plane connection over the Fs interface. In the centralizeddeployment, different functional split options between the CU 1311 andthe DUs 1312, 1313, and 1314 may be possible by locating differentprotocol layers (e.g., RAN functions) in the CU 1311 and in the DU 1312,1313, and 1314. The functional split may support flexibility to move theRAN functions between the CU 1311 and the DUs 1312, 1313, and 1314depending on service requirements and/or network environments. Thefunctional split option may change during operation (e.g., after the Fsinterface setup procedure), or the functional split option may changeonly in the Fs setup procedure (e.g., the functional split option may bestatic during operation after Fs setup procedure).

FIG. 14 shows examples for different functional split options of acentralized gNB deployment. Element numerals that are followed by “A” or“B” designations in FIG. 14 may represent the same elements in differenttraffic flows, e.g., either receiving data (e.g., data 1402A) or sendingdata (e.g., 1402B). In the split option example 1, an NR RRC 1401 may bein a CU, and an NR PDCP 1403, an NR RLC (e.g., comprising a High NR RLC1404 and/or a Low NR RLC 1405), an NR MAC (e.g., comprising a High NRMAC 1406 and/or a Low NR MAC 1407), an NR PHY (e.g., comprising a HighNR PHY 1408 and/or a LOW NR PHY 1409), and an RF 1410 may be in a DU. Inthe split option example 2, the NR RRC 1401 and the NR PDCP 1403 may bein a CU, and the NR RLC, the NR MAC, the NR PHY, and the RF 1410 may bein a DU. In the split option example 3, the NR RRC 1401, the NR PDCP1403, and a partial function of the NR RLC (e.g., the High NR RLC 1404)may be in a CU, and the other partial function of the NR RLC (e.g., theLow NR RLC 1405), the NR MAC, the NR PHY, and the RF 1410 may be in aDU. In the split option example 4, the NR RRC 1401, the NR PDCP 1403,and the NR RLC may be in a CU, and the NR MAC, the NR PHY, and the RF1410 may be in a DU. In the split option example 5, the NR RRC 1401, theNR PDCP 1403, the NR RLC, and a partial function of the NR MAC (e.g.,the High NR MAC 1406) may be in a CU, and the other partial function ofthe NR MAC (e.g., the Low NR MAC 1407), the NR PHY, and the RF 1410 maybe in a DU. In the split option example 6, the NR RRC 1401, the NR PDCP1403, the NR RLC, and the NR MAC may be in CU, and the NR PHY and the RF1410 may be in a DU. In the split option example 7, the NR RRC 1401, theNR PDCP 1403, the NR RLC, the NR MAC, and a partial function of the NRPHY (e.g., the High NR PHY 1408) may be in a CU, and the other partialfunction of the NR PHY (e.g., the Low NR PHY 1409) and the RF 1410 maybe in a DU. In the split option example 8, the NR RRC 1401, the NR PDCP1403, the NR RLC, the NR MAC, and the NR PHY may be in a CU, and the RF1410 may be in a DU.

The functional split may be configured per CU, per DU, per wirelessdevice, per bearer, per slice, and/or with other granularities. In a perCU split, a CU may have a fixed split, and DUs may be configured tomatch the split option of the CU. In a per DU split, each DU may beconfigured with a different split, and a CU may provide different splitoptions for different DUs. In a per wireless device split, a gNB (e.g.,a CU and a DU) may provide different split options for differentwireless devices. In a per bearer split, different split options may beutilized for different bearer types. In a per slice splice, differentsplit options may be applied for different slices.

A new radio access network (new RAN) may support different networkslices, which may allow differentiated treatment customized to supportdifferent service requirements with end to end scope. The new RAN mayprovide a differentiated handling of traffic for different networkslices that may be pre-configured, and the new RAN may allow a singleRAN node to support multiple slices. The new RAN may support selectionof a RAN part for a given network slice, e.g., by one or more sliceID(s) or NSSAI(s) provided by a wireless device or provided by an NGC(e.g., an NG CP). The slice ID(s) or NSSAI(s) may identify one or moreof pre-configured network slices in a PLMN. For an initial attach, awireless device may provide a slice ID and/or an NSSAI, and a RAN node(e.g., a gNB) may use the slice ID or the NSSAI for routing an initialNAS signaling to an NGC control plane function (e.g., an NG CP). If awireless device does not provide any slice ID or NSSAI, a RAN node maysend a NAS signaling to a default NGC control plane function. Forsubsequent accesses, the wireless device may provide a temporary ID fora slice identification, which may be assigned by the NGC control planefunction, to enable a RAN node to route the NAS message to a relevantNGC control plane function. The new RAN may support resource isolationbetween slices. If the RAN resource isolation is implemented, shortageof shared resources in one slice does not cause a break in a servicelevel agreement for another slice.

The amount of data traffic carried over networks is expected to increasefor many years to come. The number of users and/or devices is increasingand each user/device accesses an increasing number and variety ofservices, e.g., video delivery, large files, and images. This requiresnot only high capacity in the network, but also provisioning very highdata rates to meet customers' expectations on interactivity andresponsiveness. More spectrum may be required for network operators tomeet the increasing demand. Considering user expectations of high datarates along with seamless mobility, it is beneficial that more spectrumbe made available for deploying macro cells as well as small cells forcommunication systems.

Striving to meet the market demands, there has been increasing interestfrom operators in deploying some complementary access utilizingunlicensed spectrum to meet the traffic growth. This is exemplified bythe large number of operator-deployed Wi-Fi networks and the 3GPPstandardization of LTE/WLAN interworking solutions. This interestindicates that unlicensed spectrum, if present, may be an effectivecomplement to licensed spectrum for network operators, e.g., to helpaddress the traffic explosion in some examples, such as hotspot areas.Licensed Assisted Access (LAA) offers an alternative for operators tomake use of unlicensed spectrum, e.g., if managing one radio network,offering new possibilities for optimizing the network's efficiency.

Listen-before-talk (clear channel assessment) may be implemented fortransmission in an LAA cell. In a listen-before-talk (LBT) procedure,equipment may apply a clear channel assessment (CCA) check before usingthe channel. For example, the CCA may utilize at least energy detectionto determine the presence or absence of other signals on a channel todetermine if a channel is occupied or clear, respectively. For example,European and Japanese regulations mandate the usage of LBT in theunlicensed bands. Apart from regulatory requirements, carrier sensingvia LBT may be one way for fair sharing of the unlicensed spectrum.

Discontinuous transmission on an unlicensed carrier with limited maximumtransmission duration may be enabled. Some of these functions may besupported by one or more signals to be transmitted from the beginning ofa discontinuous LAA downlink transmission. Channel reservation may beenabled by the transmission of signals, by an LAA node, after gainingchannel access, e.g., via a successful LBT operation, so that othernodes that receive the transmitted signal with energy above a certainthreshold sense the channel to be occupied. Functions that may need tobe supported by one or more signals for LAA operation with discontinuousdownlink transmission may include one or more of the following:detection of the LAA downlink transmission (including cellidentification) by wireless devices, time synchronization of wirelessdevices, and frequency synchronization of wireless devices.

DL LAA design may employ subframe boundary alignment according to LTE-Acarrier aggregation timing relationships across serving cells aggregatedby CA. This may not indicate that the eNB transmissions may start onlyat the subframe boundary. LAA may support transmitting PDSCH if not allOFDM symbols are available for transmission in a subframe according toLBT. Delivery of necessary control information for the PDSCH may also besupported.

LBT procedures may be employed for fair and friendly coexistence of LAAwith other operators and technologies operating in unlicensed spectrum.LBT procedures on a node attempting to transmit on a carrier inunlicensed spectrum may require the node to perform a clear channelassessment to determine if the channel is free for use. An LBT proceduremay involve at least energy detection to determine if the channel isbeing used. For example, regulatory requirements in some regions, e.g.,in Europe, specify an energy detection threshold such that if a nodereceives energy greater than this threshold, the node assumes that thechannel is not free. Nodes may follow such regulatory requirements. Anode may optionally use a lower threshold for energy detection than thatspecified by regulatory requirements. LAA may employ a mechanism toadaptively change the energy detection threshold, e.g., LAA may employ amechanism to adaptively lower the energy detection threshold from anupper bound. Adaptation mechanism may not preclude static or semi-staticsetting of the threshold. A Category 4 LBT mechanism or other type ofLBT mechanisms may be implemented.

Various example LBT mechanisms may be implemented. For some signals, insome implementation scenarios, in some situations, and/or in somefrequencies, no LBT procedure may performed by the transmitting entity.For example, Category 2 (e.g., LBT without random back-off) may beimplemented. The duration of time that the channel is sensed to be idlebefore the transmitting entity transmits may be deterministic. Forexample, Category 3 (e.g., LBT with random back-off with a contentionwindow of fixed size) may be implemented. The LBT procedure may have thefollowing procedure as one of its components. The transmitting entitymay draw a random number N within a contention window. The size of thecontention window may be specified by the minimum and maximum value ofN. The size of the contention window may be fixed. The random number Nmay be employed in the LBT procedure to determine the duration of timethat the channel is sensed to be idle, e.g., before the transmittingentity transmits on the channel. For example, Category 4 (e.g., LBT withrandom back-off with a contention window of variable size) may beimplemented. The transmitting entity may draw a random number N within acontention window. The size of contention window may be specified by theminimum and maximum value of N. The transmitting entity may vary thesize of the contention window if drawing the random number N. The randomnumber N may be used in the LBT procedure to determine the duration oftime that the channel is sensed to be idle, e.g., before thetransmitting entity transmits on the channel.

LAA may employ uplink LBT at the wireless device. The UL LBT scheme maybe different from the DL LBT scheme, e.g., by using different LBTmechanisms or parameters. These differences in schemes may be due to theLAA UL being based on scheduled access, which may affect a wirelessdevice's channel contention opportunities. Other considerationsmotivating a different UL LBT scheme may include, but are not limitedto, multiplexing of multiple wireless devices in a single subframe.

A DL transmission burst may be a continuous transmission from a DLtransmitting node, e.g., with no transmission immediately before orafter from the same node on the same CC. An UL transmission burst from awireless device perspective may be a continuous transmission from awireless device, e.g., with no transmission immediately before or afterfrom the same wireless device on the same CC. A UL transmission burstmay be defined from a wireless device perspective or from an eNBperspective. If an eNB is operating DL and UL LAA over the sameunlicensed carrier, DL transmission burst(s) and UL transmissionburst(s) on LAA may be scheduled in a TDM manner over the sameunlicensed carrier. An instant in time may be part of a DL transmissionburst or part of an UL transmission burst.

A base station may transmit a plurality of beams to a wireless device. Aserving beam may be determined, from the plurality of beams, for thewireless communications between the base station and the wirelessdevice. One or more candidate beams may also be determined, from theplurality of beams, for providing the wireless communications if a beamfailure event occurs, e.g., such that the serving beam becomes unable toprovide the desired communications. One or more candidate beams may bedetermined by a wireless device and/or by a base station. By determiningand configuring a candidate beam, the wireless device and base stationmay continue wireless communications if the serving beam experiences abeam failure event.

Single beam and multi-beam operations may be supported, e.g., in a NR(New Radio) system. In a multi-beam example, a base station (e.g., a gNBin NR) may perform a downlink beam sweep to provide coverage for DLsynchronization signals (SSs) and common control channels. Wirelessdevices may perform uplink beam sweeps for UL direction to access acell. In a single beam example, a base station may configuretime-repetition within one synchronization signal (SS) block. Thistime-repetition may comprise, e.g., one or more of a primarysynchronization signal (PSS), a secondary synchronization signal (SSS),and a physical broadcast channel (PBCH). These signals may be in a widebeam. In a multi-beam example, a base station may configure one or moreof these signals and physical channels, such as an SS Block, in multiplebeams. A wireless device may identify, e.g., from an SS block, an OFDMsymbol index, a slot index in a radio frame, and a radio frame number.

In an RRC_INACTIVE state or in an RRC_IDLE state, a wireless device mayassume that SS blocks form an SS burst and an SS burst set. An SS burstset may have a given periodicity. SS blocks may be transmitted togetherin multiple beams (e.g., in multiple beam examples) to form an SS burst.One or more SS blocks may be transmitted via one beam. A beam may have asteering direction. If multiple SS bursts transmit beams, these SSbursts together may form an SS burst set, such as shown in FIG. 15. Abase station 1501 (e.g., a gNB in NR) may transmit SS bursts 1502A to1502H during time periods 1503. A plurality of these SS bursts maycomprise an SS burst set, such as an SS burst set 1504 (e.g., SS bursts1502A and 1502E). An SS burst set may comprise any number of a pluralityof SS bursts 1502A to 1502H. Each SS burst within an SS burst set maytransmitted at a fixed or variable periodicity during time periods 1503.

In a multi-beam example, one or more of PSS, SSS, or PBCH signals may berepeated for a cell, e.g., to support cell selection, cell reselection,and/or initial access procedures. For an SS burst, an associated PBCH ora physical downlink shared channel (PDSCH) scheduling system informationmay be broadcasted by a base station to multiple wireless devices. ThePDSCH may be indicated by a physical downlink control channel (PDCCH) ina common search space. The system information may comprise systeminformation block type 2 (SIB2). SIB2 may carry a physical random accesschannel (PRACH) configuration for a beam. For a beam, a base station(e.g., a gNB in NR) may have a RACH configuration which may include aPRACH preamble pool, time and/or frequency radio resources, and otherpower related parameters. A wireless device may use a PRACH preamblefrom a RACH configuration to initiate a contention-based RACH procedureor a contention-free RACH procedure. A wireless device may perform a4-step RACH procedure, which may be a contention-based RACH procedure ora contention-free RACH procedure. The wireless device may select a beamassociated with an SS block that may have the best receiving signalquality. The wireless device may successfully detect a cell identifierthat may be associated with the cell and decode system information witha RACH configuration. The wireless device may use one PRACH preamble andselect one PRACH resource from RACH resources indicated by the systeminformation associated with the selected beam. A PRACH resource maycomprise at least one of: a PRACH index indicating a PRACH preamble, aPRACH format, a PRACH numerology, time and/or frequency radio resourceallocation, power setting of a PRACH transmission, and/or other radioresource parameters. For a contention-free RACH procedure, the PRACHpreamble and resource may be indicated in a DCI or other high layersignaling.

FIG. 16 shows an example of a random access procedure (e.g., via a RACH)that may include sending, by a base station, one or more SS blocks. Awireless device 1620 (e.g., a UE) may transmit one or more preambles toa base station 1621 (e.g., a gNB in NR). Each preamble transmission bythe wireless device may be associated with a separate random accessprocedure, such as shown in FIG. 16. The random access procedure maybegin at step 1601 with a base station 1621 (e.g., a gNB in NR) sendinga first SS block to a wireless device 1621 (e.g., a UE). Any of the SSblocks may comprise one or more of a PSS, SSS, tertiary synchronizationsignal (TSS), or PBCH signal. The first SS block in step 1601 may beassociated with a first PRACH configuration. At step 1602, the basestation 1621 may send to the wireless device 1620 a second SS block thatmay be associated with a second PRACH configuration. At step 1603, thebase station 1621 may send to the wireless device 1620 a third SS blockthat may be associated with a third PRACH configuration. At step 1604,the base station 1621 may send to the wireless device 1620 a fourth SSblock that may be associated with a fourth PRACH configuration. Anynumber of SS blocks may be sent in the same manner in addition to, orreplacing, steps 1603 and 1604. An SS burst may comprise any number ofSS blocks. For example, SS burst 1610 comprises the three SS blocks sentduring steps 1602-1604.

The wireless device 1620 may send to the base station 1621 a preamble,at step 1605, e.g., after or in response to receiving one or more SSblocks or SS bursts. The preamble may comprise a PRACH preamble, and maybe referred to as RA Msg 1. The PRACH preamble may be transmitted instep 1605 according to or based on a PRACH configuration that may bereceived in an SS block (e.g., one of the SS blocks from steps1601-1604) that may be determined to be the best SS block beam. Thewireless device 1620 may determine a best SS block beam from among SSblocks it may receive prior to sending the PRACH preamble. The basestation 1621 may send a random access response (RAR), which may bereferred to as RA Msg2, at step 1606, e.g., after or in response toreceiving the PRACH preamble. The RAR may be transmitted in step 1606via a DL beam that corresponds to the SS block beam associated with thePRACH configuration. The base station 1621 may determine the best SSblock beam from among SS blocks it previously sent prior to receivingthe PRACH preamble. The base station 1621 may receive the PRACH preambleaccording to or based on the PRACH configuration associated with thebest SS block beam.

The wireless device 1620 may send to the base station 1621 anRRCConnectionRequest and/or RRCConnectionResumeRequest message, whichmay be referred to as RA Msg3, at step 1607, e.g., after or in responseto receiving the RAR. The base station 1621 may send to the wirelessdevice 1620 an RRCConnectionSetup and/or RRCConnectionResume message,which may be referred to as RA Msg4, at step 1608, e.g., after or inresponse to receiving the RRCConnectionRequest and/orRRCConnectionResumeRequest message. The wireless device 1620 may send tothe base station 1621 an RRCConnectionSetupComplete and/orRRCConnectionResumeComplete message, which may be referred to as RAMsg5, at step 1609, e.g., after or in response to receiving theRRCConnectionSetup and/or RRCConnectionResume. An RRC connection may beestablished between the wireless device 1620 and the base station 1621,and the random access procedure may end, e.g., after or in response toreceiving the RRCConnectionSetupComplete and/orRRCConnectionResumeComplete message.

A best beam, including but not limited to a best SS block beam, may bedetermined based on a channel state information reference signal(CSI-RS). A wireless device may use a CSI-RS in a multi-beam system forestimating the beam quality of the links between the wireless device anda base station. For example, based on a measurement of a CSI-RS, awireless device may report CSI for downlink channel adaption. A CSIparameter may include a precoding matrix index (PMI), a channel qualityindex (CQI) value, and/or a rank indicator (RI). A wireless device mayreport a beam index based on a reference signal received power (RSRP)measurement on a CSI-RS. The wireless device may report the beam indexin a CSI resource indication (CRI) for downlink beam selection. A basestation may transmit a CSI-RS via a CSI-RS resource, such as via one ormore antenna ports, or via one or more time and/or frequency radioresources. A beam may be associated with a CSI-RS. A CSI-RS may comprisean indication of a beam direction. Each of a plurality of beams may beassociated with one of a plurality of CSI-RSs. A CSI-RS resource may beconfigured in a cell-specific way, e.g., via common RRC signaling.Additionally or alternatively, a CSI-RS resource may be configured in awireless device-specific way, e.g., via dedicated RRC signaling and/orlayer 1 and/or layer 2 (L1/L2) signaling. Multiple wireless devices inor served by a cell may measure a cell-specific CSI-RS resource. Adedicated subset of wireless devices in or served by a cell may measurea wireless device-specific CSI-RS resource. A base station may transmita CSI-RS resource periodically, using aperiodic transmission, or using amulti-shot or semi-persistent transmission. In a periodic transmission,a base station may transmit the configured CSI-RS resource using aconfigured periodicity in the time domain. In an aperiodic transmission,a base station may transmit the configured CSI-RS resource in adedicated time slot. In a multi-shot or semi-persistent transmission, abase station may transmit the configured CSI-RS resource in a configuredperiod. A base station may configure different CSI-RS resources indifferent terms for different purposes. Different terms may include,e.g., cell-specific, device-specific, periodic, aperiodic, multi-shot,or other terms. Different purposes may include, e.g., beam management,CQI reporting, or other purposes.

FIG. 17 shows an example of transmitting CSI-RSs periodically for abeam. A base station 1701 may transmit a beam in a predefined order inthe time domain, such as during time periods 1703. Beams used for aCSI-RS transmission, such as for CSI-RS 1704 in transmissions 1702Cand/or 1703E, may have a different beam width relative to a beam widthfor SS-blocks transmission, such as for SS blocks 1702A, 1702B, 1702D,and 1702F-1702H. Additionally or alternatively, a beam width of a beamused for a CSI-RS transmission may have the same value as a beam widthfor an SS block. Some or all of one or more CSI-RSs may be included inone or more beams. An SS block may occupy a number of OFDM symbols(e.g., 4), and a number of subcarriers (e.g., 240), carrying asynchronization sequence signal. The synchronization sequence signal mayidentify a cell.

FIG. 18 shows an example of a CSI-RS that may be mapped in time andfrequency domains. Each square shown in FIG. 18 may represent a resourceblock within a bandwidth of a cell. Each resource block may comprise anumber of subcarriers. A cell may have a bandwidth comprising a numberof resource blocks. A base station (e.g., a gNB in NR) may transmit oneor more RRC messages comprising CSI-RS parameters for one or moreCSI-RS. CSI-RS parameters for a CSI-RS may comprise, e.g., time and OFDMfrequency parameters, port numbers, CSI-RS index, and/or CSI-RS sequenceparameters. Time and frequency parameters may indicate, e.g.,periodicity, subframes, symbol numbers, OFDM subcarriers, and/or otherradio resource parameters. CSI-RS may be configured using commonparameters, e.g., when a plurality of wireless devices receive the sameCSI-RS signal. CSI-RS may be configured using wireless device dedicatedparameters, e.g., when a CSI-RS is configured for a specific wirelessdevice.

As shown in FIG. 18, three beams may be configured for a wirelessdevice, e.g., in a wireless device-specific configuration. Any number ofadditional beams (e.g., represented by the column of blank squares) orfewer beams may be included. Beam 1 may be allocated with CSI-RS 1 thatmay be transmitted in some subcarriers in a resource block (RB) of afirst symbol. Beam 2 may be allocated with CSI-RS 2 that may betransmitted in some subcarriers in a RB of a second symbol. Beam 3 maybe allocated with CSI-RS 3 that may be transmitted in some subcarriersin a RB of a third symbol. All subcarriers in a RB may not necessarilybe used for transmitting a particular CSI-RS (e.g., CSI-RS1) on anassociated beam (e.g., beam 1) for that CSI-RS. By using frequencydivision multiplexing (FDM), other subcarriers, not used for beam 1 forthe wireless device in the same RB, may be used for other CSI-RStransmissions associated with a different beam for other wirelessdevices. Additionally or alternatively, by using time domainmultiplexing (TDM), beams used for a wireless device may be configuredsuch that different beams (e.g., beam 1, beam 2, and beam 3) for thewireless device may be transmitted using some symbols different frombeams of other wireless devices.

Beam management may use a device-specific configured CSI-RS. In a beammanagement procedure, a wireless device may monitor a channel quality ofa beam pair link comprising a transmitting beam by a base station (e.g.,a gNB in NR) and a receiving beam by the wireless device (e.g., a UE).When multiple CSI-RSs associated with multiple beams are configured, awireless device may monitor multiple beam pair links between the basestation and the wireless device.

A wireless device may transmit one or more beam management reports to abase station. A beam management report may indicate one or more beampair quality parameters, comprising, e.g., one or more beamidentifications, RSRP, PMI, CQI, and/or RI, of a subset of configuredbeams.

A base station and/or a wireless device may perform a downlink L1/L2beam management procedure. One or more downlink L1/L2 beam managementprocedures may be performed within one or multiple transmission andreceiving points (TRPs). Procedure P-1 may be used to enable a wirelessdevice measurement on different TRP transmit (Tx) beams, e.g., tosupport a selection of TRP Tx beams and/or wireless device receive (Rx)beam(s). Beamforming at a TRP may include, e.g., an intra-TRP and/orinter-TRP Tx beam sweep from a set of different beams. Beamforming at awireless device, may include, e.g., a wireless device Rx beam sweep froma set of different beams. Procedure P-2 may be used to enable a wirelessdevice measurement on different TRP Tx beams, e.g., which may changeinter-TRP and/or intra-TRP Tx beam(s). Procedure P-2 may be performed,e.g., on a smaller set of beams for beam refinement than in procedureP-1. P-2 may be a particular example of P-1. P-3 may be used to enable awireless device measurement on the same TRP Tx beam, e.g., to change awireless device Rx beam if a wireless device uses beamforming.

Based on a wireless device's beam management report, a base station maytransmit, to the wireless device, a signal indicating that one or morebeam pair links are the one or more serving beams. The base station maytransmit PDCCH and/or PDSCH for the wireless device using the one ormore serving beams.

A wireless device (e.g., a UE) and/or a base station (e.g., a gNB) maytrigger a beam failure recovery mechanism. A wireless device may triggera beam failure recovery (BFR) request transmission, e.g., when a beamfailure event occurs. A beam failure event may include, e.g., adetermination that a quality of beam pair link(s) of an associatedcontrol channel is unsatisfactory. A determination of an unsatisfactoryquality of beam pair link(s) of an associated channel may be based onthe quality falling below a threshold and/or an expiration of a timer.

A wireless device may measure a quality of beam pair link(s) using oneor more reference signals (RS). One or more SS blocks, one or moreCSI-RS resources, and/or one or more demodulation reference signals(DM-RSs) of a PBCH may be used as a RS for measuring a quality of a beampair link. A quality of a beam pair link may be based on one or more ofan RSRP value, reference signal received quality (RSRQ) value, and/orCSI value measured on RS resources. A base station may indicate that anRS resource, e.g., that may be used for measuring a beam pair linkquality, is quasi-co-located (QCLed) with one or more DM-RSs of acontrol channel. The RS resource and the DM-RSs of the control channelmay be QCLed when the channel characteristics from a transmission via anRS to a wireless device, and the channel characteristics from atransmission via a control channel to the wireless device, are similaror the same under a configured criterion.

FIG. 19 shows an example of a beam failure event involving a single TRP.A single TRP such as at a base station 1901 may transmit, to a wirelessdevice 1902, a first beam 1903 and a second beam 1904. A beam failureevent may occur if, e.g., a serving beam, such as the second beam 1904,is blocked by a moving vehicle 1905 or other obstruction (e.g.,building, tree, land, or any object) and configured beams (e.g., thefirst beam 1903 and the second beam 1904), including the serving beam,are received from the single TRP. The wireless device 1902 may trigger amechanism to recover from beam failure when a beam failure occurs.

FIG. 20 shows an example of a beam failure event involving multipleTRPs. Multiple TRPs, such as at a first base station 2001 and at asecond base station 2006, may transmit, to a wireless device 2002, afirst beam 2003 (e.g., from the first base station 2001) and a secondbeam 2004 (e.g., from the second base station 2006). A beam failureevent may occur when, e.g., a serving beam, such as the second beam2004, is blocked by a moving vehicle 2005 or other obstruction (e.g.,building, tree, land, or any object) and configured beams (e.g., thefirst beam 2003 and the second beam 2004) are received from multipleTRPs. The wireless device 2002 may trigger a mechanism to recover frombeam failure when a beam failure occurs.

A wireless device may monitor a PDCCH, such as a New Radio PDCCH(NR-PDCCH), on M beam pair links simultaneously, where M≥1 and themaximum value of M may depend at least on the wireless devicecapability. Such monitoring may increase robustness against beam pairlink blocking. A base station may transmit, and the wireless device mayreceive, one or more messages configured to cause the wireless device tomonitor NR-PDCCH on different beam pair link(s) and/or in differentNR-PDCCH OFDM symbols.

A base station may transmit higher layer signaling, and/or a MAC controlelement (MAC CE), that may comprise parameters related to a wirelessdevice Rx beam setting for monitoring NR-PDCCH on multiple beam pairlinks. A base station may transmit one or more indications of a spatialQCL assumption between a first DL RS antenna port(s) and a second DL RSantenna port(s). The first DL RS antenna port(s) may be for one or moreof a cell-specific CSI-RS, device-specific CSI-RS, SS block, PBCH withDM-RSs of PBCH, and/or PBCH without DM-RSs of PBCH. The second DL RSantenna port(s) may be for demodulation of a DL control channel.Signaling for a beam indication for a NR-PDCCH (e.g., configuration tomonitor NR-PDCCH) may be via MAC CE signaling, RRC signaling, DCIsignaling, or specification-transparent and/or an implicit method, andany combination thereof.

For reception of unicast DL data channel, a base station may indicatespatial QCL parameters between DL RS antenna port(s) and DM-RS antennaport(s) of DL data channel. A base station may transmit DCI (e.g.,downlink grants) comprising information indicating the RS antennaport(s). The information may indicate the RS antenna port(s) which maybe QCLed with DM-RS antenna port(s). A different set of DM-RS antennaport(s) for the DL data channel may be indicated as a QCL with adifferent set of RS antenna port(s).

If a base station transmits a signal indicating a spatial QCL parametersbetween CSI-RS and DM-RS for PDCCH, a wireless device may use CSI-RSsQCLed with DM-RS for a PDCCH to monitor beam pair link quality. If abeam failure event occurs, the wireless device may transmit a beamfailure recovery request, such as by a determined configuration.

If a wireless device transmits a beam failure recovery request, e.g.,via an uplink physical channel or signal, a base station may detect thatthere is a beam failure event, for the wireless device, by monitoringthe uplink physical channel or signal. The base station may initiate abeam recovery mechanism to recover the beam pair link for transmittingPDCCH between the base station and the wireless device. The base stationmay transmit one or more control signals, to the wireless device, e.g.,after or in response to receiving the beam failure recovery request. Abeam recovery mechanism may be, e.g., an L1 scheme, or a higher layerscheme.

A base station may transmit one or more messages comprising, e.g.,configuration parameters of an uplink physical channel and/or a signalfor transmitting a beam failure recovery request. The uplink physicalchannel and/or signal may be based on at least one of the following: anon-contention based PRACH (e.g., a beam failure recovery PRACH orBFR-PRACH), which may use a resource orthogonal to resources of otherPRACH transmissions; a PUCCH (e.g., beam failure recovery PUCCH orBFR-PUCCH); and/or a contention-based PRACH resource. Combinations ofthese candidate signal and/or channels may be configured by a basestation.

If a beam failure occurs, a beam failure recovery procedure may beperformed. A wireless device may send, to a base station, a beam failurerecovery (BFR) request. The wireless device may send the BFR requestvia, e.g., a PRACH resource. Different types of BFR requests may be sentbased on a type of beam failure. As an example, a wireless device maytransmit a type 1 BFR request or a type 2 BFR request. Examples for type1 and type 2 BFR requests are provided, however, any number of differenttypes of BFR requests may be used, e.g., to indicate any number ofdifferent conditions. A base station may send, to the wireless device, aBFR type indicator. The BFR type indicator may provide an indication tothe wireless device, e.g., prior to the wireless device experiencing abeam failure event, what type of BFR request to send after detecting abeam failure. The BFR type indicator may indicate whether the wirelessdevice must determine one or more candidate beams, and/or whether thewireless device should not determine any candidate beams.

By determining and using a BFR type indicator, a BFR request mayindicate an occurrence of the beam failure detected at the wirelessdevice (e.g., a wireless device may transmit a BFR request to a basestation in response to identifying a beam failure). A BFR request mayindicate the occurrence of the beam failure that may be detected by awireless device, and/or a BFR request may indicate a candidate beam thatmay be selected by a wireless device. By determining whether a basestation or a device should determine one or candidate beams, advantagesmay be provided. For example, detecting a beam failure may take lesspower of the wireless device than both detecting the beam failure andidentifying a candidate beam. Additionally or alternatively, detecting abeam failure may take less time for a wireless device than bothdetecting a beam failure and identifying a candidate beam. A basestation may take less time to recover the beam pair link if, e.g., awireless device provides the candidate beam in a BFR request, than thetime that may take the base station to recover the beam pair link if,e.g., the wireless device does not provide candidate beam information.As another example, a wireless device may not be capable of identifyinga candidate beam, e.g., due to lack of beam correspondence between atransmitting beam and a receiving beam. Or, a wireless device may becapable of identifying a candidate beam. By enabling a base stationand/or a wireless device to decide a type of BFR request that will betransmitted if a beam failure occurs improvements may include, e.g.,reduced battery or power consumption by a wireless device, and/orreduced time spent by a base station and/or by a wireless device for aBFR procedure.

A type 1 BFR request may correspond to a BFR request that lackscandidate beam identifier information. A base station may indicate in amessage to a wireless device that the wireless device is not to providea candidate beam identifier information in a BFR request. A wirelessdevice may use a PRACH, associated with a CSI-RS resource, to transmit atype 1 BFR request corresponding to the CSI-RS resource, if a triggeringcondition is met. A triggering condition for a type 1 BFR request maycomprise a determination that the RSRP of the CSI-RS is lower than afirst threshold. Additionally or alternatively, the triggering conditionfor a type 1 BFR request may comprise an expiration of a first timerassociated with a condition, such as a duration of the RSRP of theCSI-RS being lower than the first threshold. The first threshold and/orthe first timer may be associated with a predefined value. Additionallyor alternatively, the first threshold and/or the first timer may beconfigured by one or more messages. A type 1 BFR request may betriggered by each of a plurality of conditions or by the occurrence ofall or some combination of a plurality of conditions. A plurality ofthresholds may be used, and/or a plurality of timers may be used, todetermine whether a triggering condition for a type 1 BFR request hasoccurred.

A type 2 BFR request may correspond to a BFR request that includescandidate beam identifier information. A base station may indicate in amessage to a wireless device that the wireless device is to providecandidate beam identifier information in a BFR request. A type 2 BFRrequest may be indicated by a base station if, e.g., a wireless devicehas indicated a capability to make a candidate beam selection and/or ifthe base station determines that the wireless device may have betterinformation or capability to make a candidate beam selection for itselfthan the base station may be able to do for the wireless device. Awireless device may use a PRACH, associated with a CSI-RS resource, totransmit a type 2 BFR request corresponding to the CSI-RS resource, if atriggering condition is met. The type 2 BFR request may indicate acandidate beam associated with the CSI-RS and the PRACH resource. Atriggering condition for a type 2 BFR request may comprise adetermination that the RSRP of the one or multiple serving beams islower than a second threshold. Additionally or alternatively, thetriggering condition for a type 2 BFR request may comprise an expirationof a second timer associated with a condition, such as a duration of theRSRP of the one or multiple serving beams being lower than the secondthreshold. The second threshold and/or the second timer may beassociated with a predefined value. Additionally or alternatively, thesecond threshold and/or the second timer may be configured by one ormore messages. A type 2 BFR request may be triggered by each of aplurality of conditions or by the occurrence of all or some combinationof a plurality of conditions. A plurality of thresholds may be used,and/or a plurality of timers may be used, to determine whether atriggering condition for a type 2 BFR request has occurred. As anexample, a triggering condition for a type 2 BFR request may comprise adetermination that the RSRP of a candidate beam is higher than a thirdthreshold, and/or upon the expiration of a third timer. As anotherexample, a triggering condition for a type 2 BFR request may comprise acombination of both the RSRP of one or multiple serving beams beinglower than a second threshold and the RSRP of a candidate beam beinghigher than a third threshold. Any of the above conditions may befurther based on an expiration of one or more timers, such that thecondition must be present for a duration of time until a triggeringcondition is satisfied. The second threshold may be the same ordifferent from (e.g., greater or less than) the third threshold, and thesecond and/or third threshold referenced above for type 2 BFR requestsmay be the same or different from (e.g., greater or less than) the firstthreshold referenced above for type 1 BFR requests.

To determine a beam failure event and/or to determine a candidate beam,a wireless device may measure RSRP based on CSI-RS RSRP or other RSs. Awireless device may measure RSRP, e.g., on one or multiple SS blocks,and/or on one or multiple DM-RSs on a PBCH. A base station may transmit,to the wireless device, one or more messages indicating an RS resourceto be used for the measurement, and/or indicating an RS resource to beused for the measurement is QCLed with DM-RSs of a downlink controlchannel. A wireless device may measure a RSRQ value, or a CSI valuebased on RS resources, e.g., to determine a quality of a candidate beamand/or a beam pair link.

A base station may configure a wireless device with a type of BFRrequest by using a RRC signaling. A base station may send one or moreRRC messages comprising configuration parameters of a cell. Theconfiguration parameters may comprise one or more first reference signalresource parameters of a first plurality of reference signals, one ormore second reference signal resource parameters of a second pluralityof reference signals, one or more random access preambles, and/or a beamfailure recovery type indicator (e.g., indicating a type 1 BFR requestor a type 2 BFR request).

A wireless device may receive at least one radio resource control (RRC)message comprising configuration parameters of a cell. The configurationparameters may comprise, e.g., one or more channel state informationreference signal (CSI-RS) resource parameters of a plurality of CSI-RSs;and/or one or more parameters indicating that a first type beam failurerecovery request, and/or a second type beam failure recovery request, isconfigured for the cell. Each CSI-RS may be associated with a beam. Thewireless device may detect beam failure and/or whether the one or morebeams associated with the one or more CSI-RSs meet a criterion. Thewireless device may transmit a first preamble via a RACH resources of afirst beam associated with a serving beam. Additionally oralternatively, the wireless may transmit a first preamble on multipleRACH resources associated with multiple beams.

A wireless device may receive, from a base station, one or more radioresource control messages comprising configuration parameters of a cell.The configuration parameters may comprise one or more first referencesignal resource parameters of a first plurality of reference signals,one or more second reference signal resource parameters of a secondplurality of reference signals, one or more random access preambles, anda beam failure recovery type indicator. The second plurality ofreference signals may comprise at least one or more synchronizationsignal blocks, demodulation reference signals of a physical broadcastchannel, or channel state information reference signals. The wirelessdevice may detect, based on at least one of the first plurality ofreference signals, at least one beam failure. The wireless device maydetect at least one beam failure by determining that a first channelquality of at least one first reference signal of the first plurality ofreference signals is below a first threshold, and/or by determining thata second channel quality of at least one second reference signal of thesecond plurality of reference signals is above a second threshold. Thewireless device may select, e.g., after detecting at least one beamfailure, a preamble of the one or more random access preambles. Thewireless device may base its selection of a preamble on the beam failurerecovery type indicator and a channel quality of the second plurality ofreference signals. The wireless device may base its selection of apreamble on whether the wireless device detects at least one candidatereference signal of the second plurality of reference signals. Thewireless device may transmit, via the cell, the selected preamble. Thewireless device may transmit, based on the beam failure recovery typeindicator indicating a beam failure recovery type other than a firstbeam failure recovery type (e.g., a type 2 BFR type or another BFR typeother than a type 1 BFR type), an indication of a candidate beam.

A wireless device may receive, from a base station one or more radioresource control messages comprising configuration parameters of a cell,wherein the configuration parameters may comprise one or more resourceparameters of a plurality of reference signals, and a beam failurerecovery type indicator. The plurality of reference signals may compriseat least one of synchronization signal blocks, demodulation referencesignals of a physical broadcast channel, or channel state informationreference signals. The wireless device may detect, based on one or moreof the plurality of reference signals, at least one beam failure. Thewireless device may detect the at least one beam failure by, e.g.,determining that a first channel quality of at least one first referencesignal of the plurality of reference signals is below a first threshold,and/or determining that a second channel quality of at least one secondreference signal of the plurality of reference signals is above a secondthreshold. The wireless device may determine, based on the beam failurerecovery type indicator, a type of a beam failure recovery request forthe at least one beam failure. Based on the type of the beam failurerecovery request, the wireless device may select a first availablerandom access channel resource for a transmission of the beam failurerecovery request, or select a second random access channel resource,different from the first available random access channel resource, forthe transmission of the beam failure recovery request. The wirelessdevice may transmit, via the selected random access channel resource,the beam failure recovery request. The wireless device may search, basedon the plurality of reference signals, for a candidate beam, select thesecond random access channel resource for the transmission of the beamfailure recovery request, and transmit, via the second random accesschannel resource, the beam failure recovery request. Based on thesearching, the wireless device may determine the candidate beam, and thewireless device may select the second random access channel resource byselecting a random access channel resource associated with the candidatebeam. The wireless device may determine, prior to selecting the secondrandom access channel resource for the transmission of the beam failurerecovery request, that the searching for the candidate beam isunsuccessful.

A base station may determine, based on at least one of a first pluralityof reference signals, at least one beam failure associated with awireless device. The base station may determine, based on the at leastone beam failure, a beam failure recovery type. The base station maydetermine the at least one beam failure by determining that a firstchannel quality of at least one first reference signal of the firstplurality of reference signals is below a first threshold, and/or bydetermining that a second channel quality of at least one secondreference signal of the second plurality of reference signals is above asecond threshold. The base station may transmit, to the wireless device,one or more radio resource control messages comprising configurationparameters of a cell. The configuration parameters may comprise one ormore first reference signal resource parameters of the first pluralityof reference signals, one or more second reference signal resourceparameters of a second plurality of reference signals, one or morerandom access preambles, and a beam failure recovery type indicator. Thefirst plurality of reference signals and/or the second plurality ofreference signals may comprise at least one or synchronization signalblocks, demodulation reference signals of a physical broadcast channel,or channel state information reference signals. The base station mayreceive, from the wireless device via the cell, the preamble. Thepreamble may be based on the beam failure recovery type indicator, and achannel quality of the second plurality of reference signals. Byreceiving the preamble, the base station may receive an indication of acandidate beam. The base station may make a determination, based onreceiving the preamble, whether the wireless device received the beamfailure recovery type indicator. A system may comprise a wireless deviceand a base station.

FIG. 21 shows an example of BFR request transmissions for differentrequest types. A base station 2101 may transmit a plurality of transmitbeams, e.g., TxB1 to TxB9. Nine transmit beams are shown, however, thebase station 2101 may transmit any number of transmit beams. Thetransmit beams may comprise a serving beam, such as TxB1, as well as oneor more configured and/or activated beams, such as TxB5 and TxB8. Eachbeam may have an associated CSI-RS configuration, such as CSI-RS1 toCSI-RS3, and/or an associated BFR-PRACH configuration (or RACHresource), such as R1 to R3. The base station 2101 may transmit one ormore messages comprising configuration parameters indicating one ofmultiple types of BFR requests that a wireless device 2102 may transmit.The wireless device 2102 may transmit a BFR request with informationthat may differ depending on a type (e.g., type 1 or type 2) of the BFRrequest. In the example 2103, if a type 1 BFR request is configured, thewireless device 2102 may transmit a BFR request on a RACH resource R1 ifa beam failure occurs on a beam pair link between a serving beam TxB1 ofthe base station 2101 and a receiving beam of the wireless device. Inthe example 2104, if a type 2 BFR request is configured, the wirelessdevice 2102 may transmit a BFR request on a RACH resource R2 indicatinga beam B5 as a candidate beam, if the wireless device 2102 determinesthat a beam failure event has occurred on beam B1 and the wirelessdevice 2102 determines that beam 5 is a candidate beam.

The base station 2101 may transmit to the wireless device 2102 one ormore messages comprising configuration parameters indicating a firsttype BFR request or a second type BFR request. The wireless device 2102may determine a beam failure on one or multiple serving beams, such asTxB1. The wireless device 2101 may determine a beam failure based on,e.g., measurement on RSs associated with the one or multiple servingbeams. If the wireless device 2102 receives the one or more messagescomprises configuration parameters that indicate a first type of BFRrequest, e.g., after or in response to determining a beam failure, thewireless device 2102 may transmit a first type BFR request on theBFR-PRACH resource associated with the one or multiple serving beams. Ifthe wireless device 2102 receives the one or more messages comprisesconfiguration parameters that indicate a second type of BFR request,e.g., after or in response to determining a beam failure, the wirelessdevice 2102 may identify a candidate beam, e.g., from configured oractivated multiple beams. The wireless device 2102 may also use theBFR-PRACH resource associated with the candidate beam to indicate theidentified candidate beam associated with the BFR-PRACH. If the wirelessdevice 2102 does not identify a candidate beam from configured oractivated multiple beams, the wireless device 2102 may use the BFR-PRACHresource associated with the one or multiple serving beams to transmit aBFR request, indicating that there is no candidate beam.

The wireless device 2102 may determine a beam failure based one or morebeam measurements. A beam failure may be determined for one or multipleserving beams. A beam failure may be determined based on one or moremeasurements on RSs associated with the one or multiple serving beams. Abeam failure may be determined if, e.g., measurement on one or multiplebeams are below a first threshold. Additionally or alternatively, a beamfailure determination may be based on an expiration of a first timerassociated with a condition. The wireless device 2102 may measure RSRP,e.g., based on CSI-RS RSRP or other RSs, for determining a beam failureevent. For example, the wireless device 2102 may measure RSRP on one ormultiple SS blocks, and/or one or multiple DM-RSs on PBCH. A beamfailure determination may be based on any or more of the triggeringconditions described herein.

The wireless device 2102 may identify a candidate beam based on one ormore beam measurements. A candidate beam may be determined if, e.g.,measurement on one or multiple beams are above a second threshold.Additionally or alternatively, a candidate beam determination may bebased on an expiration of a second timer associated with a condition.The wireless device 2102 may measure RSRP, e.g., based on CSI-RS RSRP orother RSs, for determining a candidate beam. For example, the wirelessdevice 2102 may measure RSRP on one or multiple SS blocks and/or one ormultiple DM-RSs on PBCH. A candidate beam determination may be based onany or more of the triggering conditions described herein.

FIG. 22 shows an example of radio resource control (RRC) configurationsfor multiple beams. A base station 2201 may send, to a wireless device2202, RRC configuration parameters 2203 of a plurality of beams B1 toB11. Each beam may have an associated set of RRC configurationparameters. Beam B1 may be associated with CSI-RS1 and R1, beam B7 maybe associated with CSI-RS2 and R2, and beam B11 may be associated withCSI-RS3 and R3. Beam B1 may be a serving beam and beam B7 and beam B8may be candidate beams. If the wireless device 2202 receives RRCconfiguration parameters of beam B1, corresponding to R1, and if thewireless device 2202 detects a beam failure, the wireless device 2202may send a preamble that corresponds to those parameters and, thewireless device 2202 may send the preamble via CSI-RS1 resourcesspecified by those parameters. If the wireless device 2202 receives RRCconfiguration parameters of beam B7, corresponding to R2, and if thewireless device 2202 detects a beam failure, the wireless device 2202may send a preamble that corresponds to those parameters and, thewireless device 2202 may send the preamble via CSI-RS2 resourcesspecified by those parameters. If the wireless device 2202 receives RRCconfiguration parameters of beam B11, corresponding to R3, and if thewireless device 2202 detects a beam failure, the wireless device 2202may send a preamble that corresponds to those parameters and, thewireless device 2202 may send the preamble via CSI-RS3 resourcesspecified by those parameters. Any number of additional beams, or fewerbeams, may be included, each having an associated CSI-RS and Rparameters.

FIG. 23 shows example wireless device procedures for beam failurerecovery. A base station may transmit one or more messages comprisingconfiguration parameters indicating one or more PRACH resources to awireless device. The base station may transmit the one or more messagesvia RRC messaging. The configuration parameters may indicate a type of aBFR request (e.g., type 1 or type 2). The configuration parameters mayindicate a number of multiple BFR requests transmissions. Theconfiguration parameters may comprise one or more preambles and/or RSs.The configuration parameters may comprise one or more first preamblesand/or PRACHs associated with first RSs, one or more second preamblesand/or PRACHs associated with second RSs, and one or more third (orother number) preambles and/or PRACHs associated with third (or othernumber) RSs. At step 2301, a wireless device may receive from the basestation the configuration parameters. The configuration parameters maybe used to configure the wireless device with a transmit beam (such asTxB1 in FIG. 21) as a serving beam. The configuration parameters mayconfigure the wireless device with configured and/or activated transmitbeams (such as TxB5 and TxB8 in FIG. 21). The base station may use theserving beam to transmit, and the wireless device may use the servingbeam to receive, PDCCH signals and associated PDSCH signals for thewireless device.

The wireless device may monitor reference signals for a potential beamfailure, at step 2302, e.g., after or in response to receivingconfiguration parameters. The wireless device may monitor a first set ofRSs based on a first threshold. The first set of RSs may correspond toCSI-RSs of a serving beam. The first threshold may be determined basedon measurements from one or more previous beam failure events. The firstthreshold may be set to a value at or near an average of previous beamfailure events, or to a value above some or all previous beam failureevents. The wireless device may monitor periodically for a duration oftime (e.g., until an expiration of a timer) or until the first RSs fallbelow the first threshold.

At step 2303, the wireless device may detect a beam failure event. Adetection of a beam failure event may comprise the wireless devicedetermining that a channel quality of the first RSs fall below the firstthreshold. Additionally or alternatively, a detection of a beam failureevent may comprise one or more measurements of a channel quality fallingbelow the first threshold. The beam failure event may be on a servingbeam (e.g., on TxB1 in FIG. 21). If a beam failure event occurs on theserving beam (e.g., TxB1 in FIG. 21), the wireless device may monitorconfigured and/or activated beams.

The wireless device may determine, at step 2304, whether a type 1 BFRrequest is configured, e.g., after or in response to detecting a beamfailure event. Additionally or alternatively, the wireless device maydetermine, at step 2304, whether a type 2 BFR request, or another typeBFR request, is configured.

If a type 1 BFR request is configured, the wireless device may transmit,at step 2305, one or more BFR requests. The wireless device maytransmit, via a first RACH resource associated with first RSs, a firstBFR request. The first RACH resource may comprise the resourceassociated with a serving beam on which a beam failure event wasdetected. The first RACH resource may comprise a first available RACHresource. The wireless device may transmit BFR requests, each with aconfigured number, via multiple BFR-PRACH resources. The wireless devicemay transmit the BFR requests via BFR-PRACH resources selected based onRSRP or other criteria (e.g., RSRQ, CQI, and/or waiting time). Thewireless device may transmit the BFR request via a PRACH resource toindicate a beam failure event occurs on one or multiple serving beamsand the wireless device does not find a candidate beam. The BFR requestmay indicate that no candidate beam may be found. For example, thewireless device may use a PRACH associated with a serving beam (e.g.,TxB1) to transmit the BFR request. By transmitting the BFR request viathe serving beam, the wireless device may indicate that a beam failureevent has occurred on the serving beam. The wireless device may transmita BFR request on a BFR-PRACH (e.g., R1 in FIG. 21). The BFR-PRACH may bebased on a CSI-RS configuration (e.g., CSI-RS1 in FIG. 21). The wirelessdevice may receive the CSI-RS configuration via a serving beam (e.g.,TxB1 in FIG. 21). The base station may configure the wireless devicewith a PRACH preamble in the one or more PRACH resources, and/or thebase station may configure the wireless device with a new set ofreference signals, e.g., after or in response to receiving one or moreBFR requests.

If, however, a type 1 BFR request is not configured, beginning with step2306, the wireless device may determine one or more candidate beams. Thewireless device may determine, e.g., at step 2306, whether a type 2 BFRrequest is configured. If the wireless device is configured with asecond type BFR request transmission, the wireless device may determineone or more candidate beams. The wireless device may monitor second RSsfor a candidate beam selection based on a second threshold. The secondset of RSs may correspond to CSI-RSs of a candidate beam. The secondthreshold may be determined based on measurements from one or moreprevious serving beams or candidate beams. The second threshold may beset to a value at or near an average of previous serving beams orcandidate beams, or to a value above some or all previous serving beamsor candidate beams. The second threshold may be greater than the firstthreshold. The wireless device may monitor periodically for a durationof time (e.g., until an expiration of a timer) or until the second RSsexceed the second threshold.

At step 2307, the wireless device may determine whether a channelquality of the second RSs satisfies the second threshold. For example,if the channel quality of the second RSs is above the second threshold,the wireless device may transmit, at step 2308, a second BFR request.The wireless device may transmit the second BFR request via a secondRACH resource that may be associated with one or more of the second RSs.If the channel quality of the second RSs is not above the secondthreshold, the wireless device may transmit, at step 2309, a third BFRrequest. The wireless device may transmit the third BFR request via athird RACH resource that may be associated with the first RSs. The thirdRACH resource may comprise the resource associated with a serving beamon which a beam failure event was detected. After transmission of a BFRrequest, e.g., at step 2305, step 2308, and/or step 2309, the wirelessdevice may end the process or repeat one or more steps of FIG. 23. Forexample, the wireless device may receive new configuration parameters,or updated parameters, at step 2301, and repeat one or more of steps2302-2309 thereafter.

If the wireless device determines a candidate beam (e.g., TxB5 or TxB8in FIG. 21), the wireless device may transmit, e.g., after step 2306, aBFR request via a BFR-PRACH (e.g., R2 or R3) associated with thecandidate beam (e.g., TxB5 or TxB8). If the wireless device determines acandidate beam from configured or activated multiple beams (e.g., TxB5or TxB8), the wireless device may use the BFR-PRACH resource (e.g.,CSI-RS2 or CSI-RS3, respectively) associated with the candidate beam toindicate the determined candidate beam associated with the BFR-PRACH.The wireless device may transmit (e.g., at step 2308) the BFR requestvia a PRACH resource that may be associated with a CSI-RS resource, orvia a PRACH resource that may be associated with one or more groups ofCSI-RS resources. If the wireless device is unable to determine acandidate beam, the wireless device may transmit (e.g., at step 2309) aBFR request via a PRACH resource (e.g., R1) associated with a servingbeam (e.g., TxB1). By transmitting a BFR request via a PRACH resourceassociated with a serving beam, the wireless device may indicate thatthe serving beam has failed and that no candidate beam has beenidentified. Additionally or alternatively, if the wireless device doesnot identify a candidate beam from configured or activated multiplebeams the wireless device may transmit multiple BFR requests viamultiple BFR-PRACH resources (e.g., R1, R2, and R3), e.g., using thePRACH preamble in R1 to indicate that TxB1 fails and no candidate beamhas been determined or identified. Any number of BFR requests may betransmitted by the wireless device. One or more BFR requests may betransmitted, via a BFR-PRACH resource associated with a CSI-RS resourceof a beam, to indicate that there is no candidate beam. One or more BFRrequests may be transmitted, by the wireless device, with the PRACHpreamble associated with the BFR-PRACH resource of the one or multipleserving beams indicating that there is no candidate beam.

Any wireless device may perform any combination of one or more of theabove steps of FIG. 23. A base station, a core network device, or anyother device, may perform any combination of a step, or a complementarystep, of one or more of the above steps. Some or all of these steps maybe performed, and the order of these steps may be adjusted. For example,one or more of steps 2306 to 2309 may not be performed for a type 2 BFRrequest. As another example, step 2302 may be performed before step2301. Additional steps may also be performed.

FIG. 24 shows example base station procedures for beam failure recovery.At step 2401, a base station may determine a type of BFR request, suchas a type 1 BFR request or a type 2 BFR request. The base station maydetermine the type of BFR request based on one or more parametersassociated with the base station, a wireless device, another basestation, or any other device, e.g., that may communicate in a networkcomprising the base station. At step 2401, the base station maydetermine a list comprising CSI-RS configurations and BFR-PRACHconfigurations. Each CSI-RS configuration may be associated with aBFR-PRACH configuration in the list.

At step 2402, the base station may transmit, to the wireless device,configuration parameters, e.g., after or in response to determining thetype of BFR request. These configuration parameters may comprise, e.g.,a BFR type indicator, preambles, RSs, the list comprising the CSI-RSconfigurations and BFR-PRACH configurations, and/or an update for thelist. The base station may transmit an update for the list in an RRCmessage. The BFR indicator may comprise an indication of one or morebinary values, which may indicate, e.g., a type 1 BFR request or a type2 BFR request. The base station may transmit these configurationparameters to a wireless device via RRC messaging. The base station maytransmit, to a wireless device, a BFR type indicator at any time,including, e.g., in some or all RRC messages. After a BFR type indicatoris transmitted, the BFR type may be changed by the base station via anupdated BFR type indicator, e.g., in an RRC message.

At step 2403, the base station may receive, from the wireless device viaa PRACH resource, a preamble. The preamble and PRACH resource may beassociated with one or more of the configuration parameters transmittedby the base station in step 2402.

The base station may determine, at step 2404, whether a type of BFRrequest was type 1 (or type 2), e.g., after or in response to receivingthe preamble. The base station may determine the type of BFR request bythe BFR type determined at step 2401 and/or the BFR type indicatortransmitted at step 2402. For a type 1 BFR request (e.g., the “Yes” pathfrom step 2404), the base station may determine an occurrence of a beamfailure, at step 2405. The base station may make such a determinationbased on the preamble transmitted by the wireless device, which mayinclude, e.g., the received power of the preamble and/or one or moreindications of signal quality. For a type 2 BFR request (e.g., the “No”path from step 2404), the base station may determine one or more RSsassociated with the preamble and/or PRACH resource from step 2403.

The base station may determine, at step 2407, whether the one or moreRSs is one of a second RSs, e.g., after or in response to determiningone or more RSs. The second RSs may comprise RSs associated with acandidate beam from the base station. If the one or more RSs is one of asecond RSs (e.g., the “Yes” path from step 2407), the base station maydetermine, at step 2408, an occurrence of beam failure and candidatebeam selection by the wireless device. For example, a determination thatan RS is received from the wireless device that corresponds to a secondRS associated with a second candidate beam transmitted by the basestation may indicate that the wireless device detected a beam failureand selected the second candidate beam. If the one or more RSs is notone of a second RSs (e.g., the “No” path from step 2407), the basestation may determine, at step 2409, an occurrence of beam failurewithout a candidate beam selection by the wireless device. For example,a determination that an RS is received from the wireless device thatdoes not correspond to a second RS associated with a second candidatebeam transmitted by the base station may indicate that the wirelessdevice detected a beam failure but did not select the second candidatebeam.

After steps 2405, 2408, and/or 2409, the base station may reconfigurethe first RSs and/or the second RSs (or other RSs), the base station mayrepeat one or more steps of FIG. 24, and/or the process may end. Thebase station may perform one or more steps of FIG. 24 for some or alltransmissions of configuration parameters (e.g., for some or all RRCmessages), and/or after receiving new or updated information.

Any base station may perform any combination of one or more of the abovesteps of FIG. 24. A wireless device, a core network device, or any otherdevice, may perform any combination of a step, or a complementary step,of one or more of the above steps. Some or all of these steps may beperformed, and the order of these steps may be adjusted. For example,one or more of steps 2406 to 2409 may not be performed for a type 2 BFRrequest. As another example, step 2404 may be performed before step2403. Additional steps may also be performed.

FIG. 25 shows example procedures for determining a type of a BFRrequest, such as a type 1 BFR request or a type 2 BFR request. Some orall of the example procedures shown and described with respect to FIG.25 may be performed, e.g., as part of step 2401 described above withrespect to FIG. 24, to determine a type of BFR request. At step 2501, abase station may determine one or more parameters that may be associatedwith a device capability. The base station may determine, for a wirelessdevice, a type of BFR request based on the one or more parameters. Theone or more parameters may be stored in the base station and/or the basestation may receive the one or more parameters, e.g., from one or moreother devices. The one or more parameters may include parametersassociated with the wireless device, the base station, a target basestation, neighboring base stations, or any other device(s). Parametersassociated with the wireless device may include wireless devicecapability parameters, such as whether the wireless device is capable ofdetermining a candidate beam within a threshold time period and/orwithin a threshold amount of available power. For example, a wirelessdevice that performs monitoring with low periodicity may not havesufficient capability to determine a candidate beam and may be bestsuited for a type 1 BFR request, whereas a wireless device that performsmonitoring at a high periodicity may have sufficient capability todetermine a candidate beam (e.g., for a type 2 BFR request). Forexample, a wireless device that supports beam correspondence between atransmitting beam and a receiving beam may have sufficient capability todetermine a candidate beam (e.g., for a type 2 BFR request). A wirelessdevice that does not support beam correspondence between a transmittingbeam and a receiving beam may not have sufficient capability todetermine a candidate beam, and as a result, the wireless device may bebetter suited for a type 1 BFR request. A beam correspondence between atransmitting beam and a receiving beam may correspond to a capabilitysuch that a wireless device may determine a transmitting beam based on areceiving beam. Parameters associated with a base station may includebase station capability parameters, such as whether the base station iscapable of determining a candidate beam within a threshold time periodor within a threshold amount of available power. For example, a basestation serving more than a threshold number of wireless devices may nothave the availability to determine a candidate beam for a particularwireless device, e.g., and the base station may select a type 2 BFRrequest to indicate the wireless device should determine a candidatebeam. A base station serving a threshold number or fewer wirelessdevices may have the availability to determine a candidate beam, e.g.,and the base station may select a type 1 BFR request to indicate thewireless device should not determine candidate beam.

At step 2502, the base station may determine network information. Thebase station may determine the network information from storedinformation and/or the base station may receive the network information,e.g., from one or more other devices. Network information may include,e.g., signal quality information, indication of prior beam failure, orany information related to a network in which the base stationcommunicates. Network information may include information known to abase station that may not be known to a wireless device. For example, ifa wireless device is communicating with a plurality of base stations andexperiences a beam failure in a first direction with a first basestation (e.g., if an obstruction blocks a beam between the first basestation and the wireless device) but the wireless device maintainscommunications on a beam in a second direction with a second basestation, the first base station and the second base station maydetermine information about the beam failure (e.g., via sharinginformation among base stations) and based on that information the firstbase station and/or the second base station may have better informationfrom which to determine a candidate beam for the wireless device thanthe wireless device itself. In such an example, a type 1 BFR request maybe selected by a base station to enable the base station to determine acandidate beam for the wireless device.

At step 2503, the base station may determine whether it is capable ofdetermining one or more candidate beams for a wireless device. The basestation may determine such capability, or lack thereof, based on the oneor more parameters determined at step 2501 and/or the networkinformation determined at step 2502. If the base station determines thatit is not capable of determining one or more candidate beams for thewireless device (e.g., the “No” path from step 2503), the base stationmay select a type 2 BFR request, at step 2504. A BFR type indicator thatindicates a type 2 BFR request may indicate that the wireless deviceshould determine one or more candidate beams for a BFR request. Thewireless device may determine a candidate beam and send a BFR requestvia resources associated with the candidate beam. If the base stationdetermines that it is capable of determining one or more candidate beamsfor the wireless device (e.g., the “Yes” path from step 2503), theprocess may continue to step 2505.

At step 2505, the base station may determine whether a wireless deviceis capable of determining one or more candidate beams. The base stationmay determine such capability, or lack thereof, based on the one or moreparameters determined at step 2501 and/or the network informationdetermined at step 2502. If the base station determines that thewireless device is not capable of determining one or more candidatebeams (e.g., the “No” path from step 2505), the base station may selecta type 1 BFR request, at step 2506. A BFR type indicator that indicatesa type 1 BFR request may indicate that the wireless device should notdetermine one or more candidate beams for a BFR request. The wirelessdevice may send a BFR request via resources associated with a servingbeam on which the wireless device detected a beam failure event. If thebase station determines that the wireless device is capable ofdetermining one or more candidate beams (e.g., the “Yes” path from step2505), the base station may analyze the one or more parameters from step2501, and/or the base station may analyze the network information fromstep 2502, to determine whether the base station or the wireless deviceis better suited to determine one or more candidate beams. Based on theanalysis and determination in step 2507, the base station may select atype of BFR request (e.g., type 1 or type 2). For example, if thewireless device is better suited than the base station to determine oneor more candidate beams, the base station may select a type 2 BFRrequest. If the wireless device is not better suited than the basestation to determine one or more candidate beams, the base station mayselect a type 1 BFR request. At step 2508, the base station may updatethe one or more parameters and/or the network information withinformation from the analysis and determination in step 2507. After step2508, the base station may station may end the process, or repeat one ormore of the above steps. The base station may perform one or more stepsof FIG. 25 for some or all transmissions of configuration parameters(e.g., for some or all RRC messages), and/or after receiving new orupdated parameters or network information.

Any base station may perform any combination of one or more of the abovesteps of FIG. 25. A wireless device, a core network device, or any otherdevice, may perform any combination of a step, or a complementary step,of one or more of the above steps. Some or all of these steps may beperformed, and the order of these steps may be adjusted. For example,one or more of steps 2501 or 2502 may not be performed. As otherexamples, step 2503 may be performed before step 2505. Results of step2501 may be weighted differently from results of step 2502 for theselection of a type of a BFR request at step 2507.

Any device may perform any combination of one or more steps describedherein. A base station and/or a wireless device, or any other device,may perform any combination of a step, or a complementary step, of oneor more steps described herein. Any base station described herein may bea current base station, a serving base station, a source base station, atarget base station, or any other base station.

FIG. 26 shows general hardware elements that may be used to implementany of the various computing devices discussed herein, including, e.g.,the base station 401, the base station 1501, the base station 1621, thebase station 1701, the base station 1901, the first base station 2001,the second base station 2006, the base station 2101, the base station2201, the wireless device 406, the wireless device 1620, the wirelessdevice 1902, the wireless device 2002, the wireless device 2102, thewireless device 2202, or any other base station, wireless device, orcomputing device. The computing device 2600 may include one or moreprocessors 2601, which may execute instructions stored in the randomaccess memory (RAM) 2603, the removable media 2604 (such as a UniversalSerial Bus (USB) drive, compact disk (CD) or digital versatile disk(DVD), or floppy disk drive), or any other desired storage medium.Instructions may also be stored in an attached (or internal) hard drive2605. The computing device 2600 may also include a security processor(not shown), which may execute instructions of a one or more computerprograms to monitor the processes executing on the processor 2601 andany process that requests access to any hardware and/or softwarecomponents of the computing device 2600 (e.g., ROM 2602, RAM 2603, theremovable media 2604, the hard drive 2605, the device controller 2607, anetwork interface 2609, a GPS 2611, a Bluetooth interface 212, a WiFiinterface 2613, etc.). The computing device 2600 may include one or moreoutput devices, such as the display 2606 (e.g., a screen, a displaydevice, a monitor, a television, etc.), and may include one or moreoutput device controllers 2607, such as a video processor. There mayalso be one or more user input devices 2608, such as a remote control,keyboard, mouse, touch screen, microphone, etc. The computing device2600 may also include one or more network interfaces, such as a networkinterface 2609, which may be a wired interface, a wireless interface, ora combination of the two. The network interface 2609 may provide aninterface for the computing device 2600 to communicate with a network2610 (e.g., a RAN, or any other network). The network interface 2609 mayinclude a modem (e.g., a cable modem), and the external network 2610 mayinclude communication links, an external network, an in-home network, aprovider's wireless, coaxial, fiber, or hybrid fiber/coaxialdistribution system (e.g., a DOCSIS network), or any other desirednetwork. Additionally, the computing device 2600 may include alocation-detecting device, such as a global positioning system (GPS)microprocessor 2611, which may be configured to receive and processglobal positioning signals and determine, with possible assistance froman external server and antenna, a geographic position of the computingdevice 2600.

The example in FIG. 26 is a hardware configuration, although thecomponents shown may be implemented as software as well. Modificationsmay be made to add, remove, combine, divide, etc. components of thecomputing device 2600 as desired. Additionally, the components may beimplemented using basic computing devices and components, and the samecomponents (e.g., processor 2601, ROM storage 2602, display 2606, etc.)may be used to implement any of the other computing devices andcomponents described herein. For example, the various componentsdescribed herein may be implemented using computing devices havingcomponents such as a processor executing computer-executableinstructions stored on a computer-readable medium, as shown in FIG. 26.Some or all of the entities described herein may be software based, andmay co-exist in a common physical platform (e.g., a requesting entitymay be a separate software process and program from a dependent entity,both of which may be executed as software on a common computing device).

One or more features of the disclosure may be implemented in acomputer-usable data and/or computer-executable instructions, such as inone or more program modules, executed by one or more computers or otherdevices. Generally, program modules include routines, programs, objects,components, data structures, etc. that perform particular tasks orimplement particular abstract data types when executed by a processor ina computer or other data processing device. The computer executableinstructions may be stored on one or more computer readable media suchas a hard disk, optical disk, removable storage media, solid statememory, RAM, etc. The functionality of the program modules may becombined or distributed as desired. The functionality may be implementedin whole or in part in firmware or hardware equivalents such asintegrated circuits, field programmable gate arrays (FPGA), and thelike. Particular data structures may be used to more effectivelyimplement one or more features of the disclosure, and such datastructures are contemplated within the scope of computer executableinstructions and computer-usable data described herein.

Many of the elements in examples may be implemented as modules. A modulemay be an isolatable element that performs a defined function and has adefined interface to other elements. The modules may be implemented inhardware, software in combination with hardware, firmware, wetware(i.e., hardware with a biological element) or a combination thereof, allof which may be behaviorally equivalent. For example, modules may beimplemented as a software routine written in a computer languageconfigured to be executed by a hardware machine (such as C, C++,Fortran, Java, Basic, Matlab or the like) or a modeling/simulationprogram such as Simulink, Stateflow, GNU Octave, or LabVIEWMathScript.Additionally or alternatively, it may be possible to implement modulesusing physical hardware that incorporates discrete or programmableanalog, digital and/or quantum hardware. Examples of programmablehardware may comprise: computers, microcontrollers, microprocessors,application-specific integrated circuits (ASICs); field programmablegate arrays (FPGAs); and complex programmable logic devices (CPLDs).Computers, microcontrollers, and microprocessors may be programmed usinglanguages such as assembly, C, C++ or the like. FPGAs, ASICs, and CPLDsmay be programmed using hardware description languages (HDL), such asVHSIC hardware description language (VHDL) or Verilog, which mayconfigure connections between internal hardware modules with lesserfunctionality on a programmable device. The above mentioned technologiesmay be used in combination to provide the result of a functional module.

Systems, apparatuses, and methods may perform operations ofmulti-carrier communications described herein. Additionally oralternatively, a non-transitory tangible computer readable media maycomprise instructions executable by one or more processors configured tocause operations of multi-carrier communications described herein. Anarticle of manufacture may comprise a non-transitory tangible computerreadable machine-accessible medium having instructions encoded thereonfor enabling programmable hardware to cause a device (e.g., a wirelessdevice, wireless communicator, a UE, a base station, and the like) toenable operation of multi-carrier communications described herein. Thedevice, or one or more devices such as in a system, may include one ormore processors, memory, interfaces, and/or the like. Other examples maycomprise communication networks comprising devices such as basestations, wireless devices or user equipment (UE), servers, switches,antennas, and/or the like. Any device (e.g., a wireless device, a basestation, or any other device) or combination of devices may be used toperform any combination of one or more of steps described herein,including, e.g., any complementary step or steps of one or more of theabove steps.

Although examples are described above, features and/or steps of thoseexamples may be combined, divided, omitted, rearranged, revised, and/oraugmented in any desired manner. Various alterations, modifications, andimprovements will readily occur to those skilled in the art. Suchalterations, modifications, and improvements are intended to be part ofthis description, though not expressly stated herein, and are intendedto be within the spirit and scope of the disclosure. Accordingly, theforegoing description is by way of example only, and is not limiting.

What is claimed is:
 1. A method comprising: receiving, by a wirelessdevice from a base station, one or more messages comprising a pluralityof parameters, wherein the plurality of parameters indicates: a firstplurality of reference signals; a second plurality of reference signals;one or more random access preambles; and a beam failure recovery typeindicator; detecting, based on at least one of the first plurality ofreference signals, at least one beam failure; after the detecting the atleast one beam failure, selecting, based on the beam failure recoverytype indicator and a quality of the second plurality of referencesignals, a preamble of the one or more random access preambles; andtransmitting the selected preamble.
 2. The method of claim 1, whereinthe first plurality of reference signals comprises at least one of:synchronization signal blocks; demodulation reference signals of aphysical broadcast channel; or channel state information referencesignals.
 3. The method of claim 1, wherein the second plurality ofreference signals comprises at least one of: synchronization signalblocks; demodulation reference signals of a physical broadcast channel;or channel state information reference signals.
 4. The method of claim1, wherein the transmitting the selected preamble comprisestransmitting, based on the beam failure recovery type indicatorindicating a beam failure recovery type other than a first beam failurerecovery type, an indication of a candidate beam.
 5. The method of claim1, wherein the selecting is further based on whether the wireless devicedetects at least one candidate reference signal of the second pluralityof reference signals.
 6. The method of claim 1, wherein the detectingthe at least one beam failure comprises: determining that a quality ofat least one reference signal of the first plurality of referencesignals is below a threshold.
 7. The method of claim 1, furthercomprising: before the selecting the preamble, determining that aquality of at least one reference signal of the second plurality ofreference signals is above a threshold.
 8. A method comprising:determining, by a base station, a beam failure recovery type for awireless device; transmitting, by the base station to the wirelessdevice, one or more messages comprising a plurality of parameters,wherein the plurality of parameters indicates: a first plurality ofreference signals; a second plurality of reference signals; one or morerandom access preambles; and a beam failure recovery type indicator; andreceiving, from the wireless device, a preamble, wherein the preamble isbased on: the beam failure recovery type indicator; and a quality of thesecond plurality of reference signals.
 9. The method of claim 8, whereinthe first plurality of reference signals comprises at least one of:synchronization signal blocks; demodulation reference signals of aphysical broadcast channel; or channel state information referencesignals.
 10. The method of claim 8, wherein the second plurality ofreference signals comprises at least one of: synchronization signalblocks; demodulation reference signals of a physical broadcast channel;or channel state information reference signals.
 11. The method of claim8, wherein the receiving the preamble comprises receiving an indicationof a candidate beam.
 12. The method of claim 8, further comprisingdetermining, based on the receiving the preamble, whether the wirelessdevice received the beam failure recovery type indicator.
 13. The methodof claim 8, further comprising: determining, based on the preamble, atleast one beam failure associated with the wireless device; anddetermining that a quality of at least one reference signal of the firstplurality of reference signals is below a threshold.
 14. The method ofclaim 8, further comprising: after the receiving the preamble,determining that a quality of at least one reference signal of thesecond plurality of reference signals is above a threshold.
 15. A methodcomprising: receiving, by a wireless device from a base station, one ormore messages comprising a plurality of parameters, wherein theplurality of parameters indicates: a plurality of reference signals; anda beam failure recovery type indicator; detecting, based on at least oneof the plurality of reference signals, at least one beam failure;determining, based on the beam failure recovery type indicator, a typeof a beam failure recovery request for the at least one beam failure;and transmitting, via a random access channel resource selected based onthe type of the beam failure recovery request, a preamble associatedwith the beam failure recovery request.
 16. The method of claim 15,further comprising: selecting, based on the type of the beam failurerecovery request, the random access channel resource from: a firstavailable random access channel resource; or a second random accesschannel resource different from the first available random accesschannel resource.
 17. The method of claim 15, wherein: the plurality ofparameters indicates one or more random access preambles; and theplurality of reference signals comprises: a first plurality of referencesignals; and a second plurality of reference signals.
 18. The method ofclaim 17, further comprising: after detecting the at least one beamfailure, selecting, based on the beam failure recovery type indicatorand a quality of the second plurality of reference signals, thepreamble, wherein the detecting the at least one beam failure is basedon at least one of the first plurality of reference signals.
 19. Themethod of claim 15, further comprising: after detecting the at least onebeam failure, selecting, based on the beam failure recovery typeindicator indicating a first beam failure recovery type, a first randomaccess channel resource associated with a first reference signal,wherein the detecting the at least one beam failure is based on thefirst reference signal.
 20. The method of claim 15, further comprising:after detecting the at least one beam failure, selecting, based on thebeam failure recovery type indicator indicating a second beam failurerecovery type, a first random access channel resource associated with afirst reference signal, wherein the detecting the at least one beamfailure is based on a second reference signal associated with a secondrandom access channel resource different from the first random accesschannel resource.
 21. A method comprising: transmitting, by a basestation to a wireless device, one or more messages comprising aplurality of parameters, wherein the plurality of parameters indicates:a plurality of reference signals; and a beam failure recovery typeindicator; receiving, via a random access channel resource selectedbased on a type of a beam failure recovery request, a preambleassociated with the beam failure recovery request, wherein the type ofthe beam failure recovery request is based on the beam failure recoverytype indicator; and transmitting, to the wireless device and afterreceiving the preamble, a response for beam failure recovery.
 22. Themethod of claim 21, wherein: the plurality of parameters indicates oneor more random access preambles; and the plurality of reference signalscomprises: a first plurality of reference signals; and a secondplurality of reference signals.
 23. The method of claim 22, wherein thepreamble is associated with at least one of the second plurality ofreference signals, and wherein at least one beam failure is associatedwith at least one of the first plurality of reference signals.
 24. Themethod of claim 21, wherein: the beam failure recovery type indicatorindicates a first beam failure recovery type; the receiving the preamblecomprises receiving the preamble via a first random access channelresource associated with a first reference signal; and at least one beamfailure is associated with the first reference signal.
 25. The method ofclaim 21, wherein: the beam failure recovery type indicator indicates asecond beam failure recovery type; the receiving the preamble comprisesreceiving the preamble via a first random access channel resourceassociated with a first reference signal; and at least one beam failureis associated with a second reference signal associated with a secondrandom access channel resource different from the first random accesschannel resource.
 26. A wireless device comprising: one or moreprocessors; and memory storing instructions that, when executed by theone or more processors, cause the wireless device to: receive, from abase station, one or more messages comprising a plurality of parameters,wherein the plurality of parameters indicates: a first plurality ofreference signals; a second plurality of reference signals; one or morerandom access preambles; and a beam failure recovery type indicator;detect, based on at least one of the first plurality of referencesignals, at least one beam failure; after detecting the at least onebeam failure, select, based on the beam failure recovery type indicatorand a quality of the second plurality of reference signals, a preambleof the one or more random access preambles; and transmit the selectedpreamble.
 27. The wireless device of claim 26, wherein the firstplurality of reference signals comprises at least one of:synchronization signal blocks; demodulation reference signals of aphysical broadcast channel; or channel state information referencesignals.
 28. The wireless device of claim 26, wherein the secondplurality of reference signals comprises at least one of:synchronization signal blocks; demodulation reference signals of aphysical broadcast channel; or channel state information referencesignals.
 29. The wireless device of claim 26, wherein the instructions,when executed by the one or more processors, cause the wireless deviceto transmit the selected preamble by: transmitting, based on the beamfailure recovery type indicator indicating a beam failure recovery typeother than a first beam failure recovery type, an indication of acandidate beam.
 30. The wireless device of claim 26, wherein theinstructions, when executed by the one or more processors, cause thewireless device to select the preamble by selecting the preamble basedon whether the wireless device detects at least one candidate referencesignal of the second plurality of reference signals.
 31. The wirelessdevice of claim 26, wherein the instructions, when executed by the oneor more processors, cause the wireless device to detect the at least onebeam failure by: determining that a quality of at least one referencesignal of the first plurality of reference signals is below a threshold.32. The wireless device of claim 26, wherein the instructions, whenexecuted by the one or more processors, cause the wireless device to:before selecting the preamble, determine that a quality of at least onereference signal of the second plurality of reference signals is above athreshold.
 33. A base station comprising: one or more processors; andmemory storing instructions that, when executed by the one or moreprocessors, cause the base station to: determine a beam failure recoverytype for a wireless device; transmit, to the wireless device, one ormore messages comprising a plurality of parameters, wherein theplurality of parameters indicates: a first plurality of referencesignals; a second plurality of reference signals; one or more randomaccess preambles; and a beam failure recovery type indicator; andreceive, from the wireless device, a preamble, wherein the preamble isbased on: the beam failure recovery type indicator; and a quality of thesecond plurality of reference signals.
 34. The base station of claim 33,wherein the first plurality of reference signals comprises at least oneof: synchronization signal blocks; demodulation reference signals of aphysical broadcast channel; or channel state information referencesignals.
 35. The base station of claim 33, wherein the second pluralityof reference signals comprises at least one of: synchronization signalblocks; demodulation reference signals of a physical broadcast channel;or channel state information reference signals.
 36. The base station ofclaim 33, wherein the instructions, when executed by the one or moreprocessors, cause the base station to receive the preamble by receivingan indication of a candidate beam.
 37. The base station of claim 33,wherein the instructions, when executed by the one or more processors,cause the base station to determine, based on receiving the preamble,whether the wireless device received the beam failure recovery typeindicator.
 38. The base station of claim 33, wherein the instructions,when executed by the one or more processors, cause the base station to:determine, based on the preamble, at least one beam failure associatedwith the wireless device; and determine that a quality of at least onereference signal of the first plurality of reference signals is below athreshold.
 39. The base station of claim 33, wherein the instructions,when executed by the one or more processors, cause the base station to:after receiving the preamble, determine that a quality of at least onereference signal of the second plurality of reference signals is above athreshold.
 40. A wireless device comprising: one or more processors; andmemory storing instructions that, when executed by the one or moreprocessors, cause the wireless device to: receive, from a base station,one or more messages comprising a plurality of parameters, wherein theplurality of parameters indicates: a plurality of reference signals; anda beam failure recovery type indicator; detect, based on at least one ofthe plurality of reference signals, at least one beam failure;determine, based on the beam failure recovery type indicator, a type ofa beam failure recovery request for the at least one beam failure; andtransmit, via a random access channel resource selected based on thetype of the beam failure recovery request, a preamble associated withthe beam failure recovery request.
 41. The wireless device of claim 40,wherein the instructions, when executed by the one or more processors,cause the wireless device to: select, based on the type of the beamfailure recovery request, the random access channel resource from: afirst available random access channel resource; or a second randomaccess channel resource different from the first available random accesschannel resource.
 42. The wireless device of claim 40, wherein: theplurality of parameters indicates one or more random access preambles;and the plurality of reference signals comprises: a first plurality ofreference signals; and a second plurality of reference signals.
 43. Thewireless device of claim 42, wherein the instructions, when executed bythe one or more processors, cause the wireless device to: afterdetecting the at least one beam failure, select, based on the beamfailure recovery type indicator and a quality of the second plurality ofreference signals, the preamble; and detect the at least one beamfailure further based on at least one of the first plurality ofreference signals.
 44. The wireless device of claim 40, wherein theinstructions, when executed by the one or more processors, cause thewireless device to: after detecting the at least one beam failure,select, based on the beam failure recovery type indicator indicating afirst beam failure recovery type, a first random access channel resourceassociated with a first reference signal; and detect the at least onebeam failure further based on the first reference signal.
 45. Thewireless device of claim 40, wherein the instructions, when executed bythe one or more processors, cause the wireless device to: afterdetecting the at least one beam failure, select, based on the beamfailure recovery type indicator indicating a second beam failurerecovery type, a first random access channel resource associated with afirst reference signal; and detect the at least one beam failure furtherbased on a second reference signal associated with a second randomaccess channel resource different from the first random access channelresource.
 46. A base station comprising: one or more processors; andmemory storing instructions that, when executed by the one or moreprocessors, cause the base station to: transmit, to a wireless device,one or more messages comprising a plurality of parameters, wherein theplurality of parameters indicates: a plurality of reference signals; anda beam failure recovery type indicator; receive, via a random accesschannel resource selected based on a type of a beam failure recoveryrequest, a preamble associated with the beam failure recovery request,wherein the type of the beam failure recovery request is based on thebeam failure recovery type indicator; and transmit, to the wirelessdevice and after receiving the preamble, a response for beam failurerecovery.
 47. The base station of claim 46, wherein: the plurality ofparameters indicates one or more random access preambles; and theplurality of reference signals comprises: a first plurality of referencesignals; and a second plurality of reference signals.
 48. The basestation of claim 47, wherein the preamble is associated with at leastone of the second plurality of reference signals, and wherein at leastone beam failure is associated with at least one of the first pluralityof reference signals.
 49. The base station of claim 46, wherein: thebeam failure recovery type indicator indicates a first beam failurerecovery type; the instructions, when executed by the one or moreprocessors, cause the base station to receive the preamble by receivingthe preamble via a first random access channel resource associated witha first reference signal; and at least one beam failure is associatedwith the first reference signal.
 50. The base station of claim 46,wherein: the beam failure recovery type indicator indicates a secondbeam failure recovery type; the instructions, when executed by the oneor more processors, cause the base station to receive the preamble byreceiving the preamble via a first random access channel resourceassociated with a first reference signal; and at least one beam failureis associated with a second reference signal associated with a secondrandom access channel resource different from the first random accesschannel resource.